I am in the market for a new HDTV and the newspaper ads are using terminology that I’m unfamiliar with. Do TVs rated at “720p” provide the same quality picture as those rated at “1080p”?

Technically, the answer is no, but it may not matter. The 1080p resolution is certainly higher, but almost nobody can tell the difference between the same material shown in the two resolutions on TV screens up to around 50″ in size and at the typical distances from which people watch those screens. Not only that, but most sources of video content, with the exception of Blu-ray discs, can’t even fully utilize 1080p. Major TV networks don’t use it yet because it requires a lot of bandwidth.

If you can afford a set that can handle 1080p, you might want to buy it so that you are ready in case a lot of 1080p content one day becomes available. You might also want a 1080p set if you are a videophile; have an enormous screen or a projector that fills a large wall; or if you play a lot of Blu-ray discs and believe you can discern the difference on a typical-sized screen. Otherwise, you could save money by buying a 720p set and you might never know the difference.

In 2006, you recommended a powerline adapter for Internet access by Netgear, the XE104. Is this still a good buy or are there others by now that are better?

I haven’t tested powerline adapters, the gadgets that route computer networks over standard home electrical wiring, since that date. Netgear and its competitors — such as Linksys and Belkin — have, naturally, come out with newer, faster units since then. But I am still personally using the XE104 successfully and feel I continue to get my money’s worth from it. It is still being sold. The newer units typically have greater speed in order to do a better job of streaming video around a home, but they work in basically the same way.

I have a Windows XP system, and things work well with my cable modem in my office. But when I’m on the road using Wi-Fi, I can receive emails, but can’t reply or send out. Any idea on how to resolve this problem?

This usually happens because the Wi-Fi provider is blocking the outgoing email server (called an “SMTP” server) that you or your IT department has set up in your email program. Some providers block all such outgoing servers. There are a number of possible solutions. The simplest is to use a Web-based email service, like Gmail or Yahoo Mail, or the Web-based version of your usual service. If your email is provided by your company, you may be able to access a version of Microsoft Outlook over the Internet that will work.

Another possibility is to ask the provider at the hotel or airport what SMTP server it does allow — usually its own — and enter it into your email program’s settings, if you know how. Yet another option would be to use a data card from a cellphone carrier, which I have found can usually overcome this problem. There may be other workarounds, and I invite readers to suggest them.

You can find Mossberg’s Mailbox, and my other columns, online, free, at the new All Things Digital Web site, http://walt.allthingsd.com.

Q. Is there any way to watch high-definition TV on a Mac in real time — not downloaded from a service?

A. As on Windows computers, there are add-on TV tuners for Macs that can both receive and record TV programs in real time. Some of them can handle high-definition programming. The best-known company that sells such tuners for the Mac is called Elgato, at elgato.com.

Q. I’m interested in your perception of the Treo’s future. I currently use (and generally like) a Treo 650. I’d like to upgrade, but I’ve read recently that Palm’s future is uncertain. I wonder if you think the Treo is on a slippery slope down, while the Apple iPhone will likely improve.

A. I do believe that Palm has allowed its software to stagnate and hasn’t moved fast enough to make its hardware thinner and cheaper. However, there are also some positive signs at Palm. Its new Centro phone is pretty good, smaller and less costly than a Treo. And the company is receiving an influx of funds and talent from a group of outside investors with experience at Apple, among other places.

Palm’s fate and future may depend on the success of a project it has undertaken to create an entirely new operating system. But the outcome of that effort won’t be known for quite some time.

The iPhone, which is already very good, will likely get better, as it is just at the beginning of its life. It has raised the bar for other smart-phone makers, such as Palm, especially when it comes to software. But I expect other companies to match at least some of the iPhone’s features and style, which means Apple will have to hustle to keep its lead. In the past five years, Apple has done very well at staying ahead of competitors in the design of its computers and portable music players. But the cellphone business is full of companies with more imagination than the typical PC maker and more resources than many makers of portable music players, so the challenge for Apple will be greater.

Q. My mom is legally blind and has difficulty working with email and downloading files. I try to help her by phone, but it never works, and we live far apart, so I can’t just go over to help her. I would like to install an application on her PC where I can take over remotely from home. Do you have any suggestions for this type of application?

A. There are a number of possibilities. One very simple option is a program called CrossLoop, at crossloop.com. Some versions of Windows, such as Windows XP Professional and Windows Vista Ultimate, also have remote desktop control built in.

You can find Mossberg’s Mailbox, and my other columns, online for free at the new All Things Digital Web site, http://walt.allthingsd.com.

Write to Walter S. Mossberg at mossberg@wsj.com

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. My column last week about high-definition TVs generated intense reader interest, and hundreds of emails, many containing questions. So this is an all-HDTV edition of Mossberg’s Mailbox.

At the end of your HDTV column, you said that, after testing a borrowed plasma HDTV, you went out and bought your own HDTV. Don’t leave us hanging. What set did you buy? And do you get a discount?

I bought the same 50-inch plasma set I tested, the Pioneer Elite PRO-1140HD. But I want to emphasize that this is a matter of personal taste (which picture you personally prefer), budget, and the style and size of the room where it’ll be used. Other brands and other technologies are also very good, and some folks might prefer them.

I don’t accept free goods, or even discounts, from companies whose products I review, as that would be unethical. So, I went to a local store and bought the Pioneer at retail, like anyone else.

You didn’t mention a burning issue in the HDTV arena right now: whether to spend the extra money to get a set that can handle the highest resolution, called “1080p”. What’s your view on this issue?

I didn’t mention it because I don’t think it’s an important factor at all. Most HDTV sets max out at a resolution called “1080i,” which is gorgeous and is used by several of the TV networks currently broadcasting in HD. Theoretically, a resolution called “1080p” is even better (I won’t go into the boring techie details of the difference) and it will be used by some new gadgets, like certain game consoles and players that handle the new disk formats battling to succeed DVD. It can also be used by PCs connected to a TV set.

But there is no TV network using 1080p, or planning to use it, anytime soon. Plus, most people can’t tell the difference between 1080i and 1080p, especially at the distances at which people typically sit to view large-screen TVs.

So, unless you are a techie, or a hard-core gamer or videophile — or you plan to use your HDTV mainly as a PC screen — I see no reason to spend a penny extra, or wait a day more, just to get a set capable of handling 1080p. If you like a set for other reasons, and it happens to have 1080p capability, think of it as a bonus. But I wouldn’t make 1080p a major criterion for choosing a set.

You talked about getting HD content via cable or satellite, but I understand you can pluck HDTV shows right out of the air, for free. Is this true?

Yes, it is, for a limited number of channels. In most cities, local affiliates of the major broadcast networks, as well as public-TV stations, beam out special digital channels that carry HD versions of popular shows. These digital channels are also available on cable, but you don’t have to pay a cable bill to view them over the air. In some cases, you can also get over-the-air digital channels from local independent stations.

Many people love over-the-air HDTV, and some say it looks even better than HD programming delivered over cable and satellite.

However, there are some downsides. First, you have to install an antenna. In some cases, this can be a relatively cheap, unobtrusive indoor antenna, but in other cases you may require a roof antenna, or even a motorized roof antenna that rotates. More important, if you rely solely on over-the-air HDTV, you won’t have access to the cable networks, like HBO, ESPN, TNT, Showtime, and Discovery, that are broadcasting movies and TV shows in HD. And you won’t have access to the special cable and satellite sports packages that bring you all the games from all over the country, which look glorious in HD.

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Because of the volume of email I receive, I can’t routinely answer individual questions by email, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com

If you have a question, send it to me at mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.

You recently recommended antispyware programs for Windows users. Do Apple Macintosh users need such software, and, if so, what products clean up spyware on the Mac?

There’s little or no reported spyware for Apple’s Mac OS X operating system. So the spyware problem isn’t much of a headache for Mac users, and consequently, there isn’t much of a market for Mac antispyware software.

Most spyware and adware consists of malicious programs, and, like regular programs, these harmful applications have to be written to run on a particular operating system. All the spyware programs I have seen, or heard about, are written to run on Windows, which is on the vast majority of the world’s PCs, and is also easier for spyware programs to penetrate than the Mac operating system is. Because they are Windows programs, they simply won’t run on the Mac, even if Mac users accidentally download them.

One type of spyware, called tracking cookies, doesn’t take the form of an actual program, and can be used on Macs. There are a few antispyware and cookie-control utilities for the Mac that may be effective against these tracking cookies, such as Internet Cleanup from Allume Software (www.allume.com). But, unlike their Windows counterparts, I haven’t tested any of them, and can’t say how well they work.

Mac users who run Apple’s built-in Safari Web browser can stop most tracking cookies by going to the Security portion of the Preferences panel and selecting the option to accept only cookies placed by the site they are using, which eliminates cookies placed by third-party advertising companies. A similar option is available in the Firefox Web browser, on both Mac and Windows. On the Mac, it’s in Firefox’s Preferences panel, under Privacy.

I’m at a loss as to where to find blogs on the Web. Are there blog search engines that help compile and categorize blogs for public perusal?

Yes. You can search or browse Web logs, or blogs, at several sites such as Feedster (feedster.com), Bloglines (bloglines.com) and Technorati (technorati.com).

You can also install special programs that let you find, and subscribe free of charge, to numerous blogs and other frequently updated Web sites. These include FeedDemon for Windows (feeddemon.com) and NetNewsWire on the Mac (ranchero.com/net newswire/).

With these programs, called news readers, you don’t usually see the blog in its original form, you receive “feeds” from them — constantly updated headlines and summaries of new entries. You can then read the entire item by just clicking on the headline.

I’ve been shopping for a TV that can receive broadcast high-definition signals, and notice many described as “HD-ready.” What does that mean?

To receive and display high-definition programming, a TV set needs two basic features. One is a display capable of rendering the high-definition picture. The other is a tuner, or receiver, capable of receiving the high-definition signal, either over the air, or from a cable or satellite service.

When a TV set is described as “HD-ready,” it usually means the set can display high-definition pictures, but lacks the special tuner needed to receive them. It may have no tuner at all built in, or it may have just a standard tuner. With this type of TV, you must buy a separate high-definition over-the-air tuner, or obtain a high-definition cable or satellite receiver, to get high-definition programming.

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Because of the volume of e-mail I receive, I can’t routinely answer individual questions by e-mail, or consult on individual problems or purchasing decisions. I read all questions I receive and select three each week to answer in the column.

Write to Walter S. Mossberg at mossberg@wsj.com