Last week, when you wrote about the ChaCha cellphone search service, you didn’t say how they make money. Are they collecting phone numbers from customers so they can send spam text messages, or sell the numbers to others who will do so?

ChaCha allows you to ask any Web-searchable question, by speaking it or texting it over a mobile phone, and then it sends you the answer via text message. The company charges consumers nothing, but says it is hoping to make money by striking deals with cellphone carriers to incorporate the ChaCha service into their current 411 phone-number look-up services. Also, it hopes to eventually include ads in the text message answers it provides.

In addition to the message that includes the answer, ChaCha sends you a message saying it is working on your request and restating your question, so you can see if it understood you correctly. It also sends an introductory text message to first-time users and occasional tips on how to use the service. Scott Jones, ChaCha’s chief executive, asserts that “we do not spam” and “we never make phone numbers and/or email addresses available to others.” He said the company is updating its privacy policy to make that clearer.

We have DSL service. I use several Web-based applications, one of which is online backup, and my husband is concerned that they degrade his use of the Web, which includes creating Web sites. I contend that that is like saying turning on one light bulb is using too much electricity, that two people on one DSL line aren’t using up too much bandwidth. Who is right?

Every situation differs, depending on exactly which programs you are each using, how you have them set, whether you are using them simultaneously, and how fast your DSL connection is. However, in general, your husband is correct that it is possible for heavy Internet usage on one computer in a home to slow down Internet speeds on another.

This is especially true with something like online backup, because it relies on your DSL account’s upload speed, which is typically far slower than the download speed. If your online backup program is trying to push a bunch of files over a slow upload connection, while he is in another room trying to upload new versions of a Web site over the same narrow upload pipe, it could affect the speeds he gets. You might try coordinating or staggering those online activities that involve heavy uploading. Normal Web surfing or emailing shouldn’t require any such coordination.

I am thinking about purchasing a Dell (DELL) XPS One all-in-one desktop, but I have one question. Does the Dell’s built-in TV tuner require any extra attachments to watch TV right out of the box?

You can watch over-the-air stations and analog basic cable stations right out of the box, without added equipment. However, you may want to connect a small desktop antenna to improve reception, which is what I did when I tested this machine. To use the XPS One with digital or premium cable or satellite stations, you would have to connect it to a cable or satellite receiver, just as most people do with their TV sets. This requires the use of an adapter that comes with the machine.

• 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.

I couldn’t find any columns on products you recommend for monitoring kids’ Web access and installing parental controls. I recently purchased a new computer for my 9-year-old daughter. I want to make sure she can only access specific Web sites and I want to protect her from inappropriate spam and chatting.

If you have a computer running one of the newer versions of Windows or the Macintosh operating system, I recommend using the extensive parental controls that are now built right into those operating systems. While you can never underestimate the ingenuity of computer-savvy kids, these built-in controls, if properly used, are generally harder to evade than the ones provided by third-party software.

I did recently review these built-in parental controls, which appear in Windows Vista, and in the Tiger and Leopard editions of the Mac’s OS X operating system. You can find that column at: ptech.allthingsd.com/20070614.

I want to switch to a Mac, but my life is on Microsoft Outlook, which is only available on Windows. Is there a simple way to convert all of this data to programs on the Mac?

There is a $10 program that performs this task. It’s called O2M (Outlook to Mac) and is from a company called Little Machines. It can be downloaded at littlemachines.com, where you also will find details about the Mac programs with which it works. This is a Windows program, which transfers your Outlook data into files you copy to your Mac. You then manually import these files into your Mac programs.

According to the company, the program exports Outlook email, email attachments, contacts and calendar appointments and allows you to import this data into Apple’s built-in email, address book and calendar programs, as well as into Microsoft Entourage, and other third-party programs.

Another approach is to install Windows on your Mac, and keep running Outlook. If you do this using the Parallels or Fusion virtualization programs ($80 each, plus the cost of Windows,) you can run Outlook simultaneously with your Mac programs.

Does the new version of Microsoft Office for the Mac work on pre-Intel Mac models?

Microsoft says it does, though I didn’t test it on one of these older machines. According to Microsoft, the new Office 2008 runs on any Mac “with an Intel, PowerPC G5, or PowerPC G4 (500 MHz or faster) processor.” However, you also need a relatively recent version of the Mac operating system, either the new Leopard edition, or the latest update (called 10.4.9) of the Tiger edition.

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.

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. This week my mailbox contained questions about antispam systems, programs to transfer files from PC to iPod and the VoiceOver system on Macs.

What is the best antispam system out there today? Spam filters don’t seem to work well for me.

Spammers change tactics so frequently that even the best, most adaptive filtering systems have a tough time coping. In my view, the strongest antispam approach isn’t filtering at all, but is called a challenge-response system.

With this approach, you set up a “white list” of approved senders — it could be your address book or some other list — and every email you get from anyone who isn’t on the list gets challenged. What this means is that the incoming email is intercepted and that the sender receives a message asking him or her to enter a constantly changing code number to prove that the message originated with a human.

The computer programs that blast out millions of spam messages usually can’t type in such a number, because it is presented as a graphic and in a wavy or faint typeface, and computers typically can’t copy and paste such graphical numerals automatically.

Messages that pass the challenge are delivered to you. Those that don’t, including nearly all spam, aren’t. Examples of such services are ChoiceMail, at digiportal.com; and EarthLink antispam, at earthlink.net.

The downside of this approach is that legitimate senders not on your list may find it a hassle to fill out the challenge and give up on emailing you. This is a problem mainly for business users who get desired emails from people they don’t know, such as prospective customers.

I would like to transfer files onto a new PC from my iPod. Are there any programs that do this?

There are multiple inexpensive programs designed to do exactly that. Some work with Windows computers, some with Apple Macintosh computers, and some have versions for both. One that I have found reliable is a British-made program called Music Rescue (formerly known as PodUtil) and can be found at www.kennettnet.co.uk/musicrescue/. It comes in both Windows and Mac versions and costs £10, or about $19.40.

Ever since I changed batteries 10 days ago in the wireless keyboard for my Apple iBook G4, there has been a voice that seems to be issuing commands to the computer, or at least is speaking what is happening when I do things. I must have done something wrong. How can I stop it?

I assume that, while fumbling with the keyboard to change the batteries, you accidentally turned on a feature called VoiceOver in Apple’s Mac OS X operating system that speaks aloud various alerts and actions. This feature is intended for certain disabled users who have difficulty seeing the screen or otherwise could benefit from spoken feedback when navigating their computer’s interface.

To turn VoiceOver off, you can just press the command (Apple) key and the F5 key simultaneously, though on a laptop such as yours you may have to also hold down the Function (fn) key at the same time. Or, you can launch System Preferences, select Universal Access, and then select the tab labeled “Seeing” and click the Off button under VoiceOver.

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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