In this column, I will answer some common questions about software for online auction users. Some of these questions are ones I have been frequently asked, while others address areas that are not well understood, or have myths to dispel. If you have a question you would like to see answered here, please contact me at the email address below.

Today's question is "What is Skype?"

eBay announced this week it would acquire Skype for several billion dollars (http://auctionbytes.com/cab/abn/y05/m09/i12/s00), so this is a timely topic.

Skype is a free download that lets you use your computer to make telephone calls. Calls from one Skype user to another are free, wherever they are in the world. You make calls using usernames rather than traditional phone numbers, and an instant-messaging client (for text chatting) is included. Skype does not carry adware or spyware.

There are a number of paid add-ons: SkypeOut, for calling ordinary phones; SkypeIn, which provides a real phone number so non-Skype users can call you; and Skype Voicemail, to answer your calls when you are away from the PC. With these services, Skype can provide its users with a rich set of features at low cost.

To use Skype you need a PC running Windows, Mac OS X, or Linux, or a PDA with Windows Pocket PC 2003. You also need an Internet connection, a headset or equivalent, and the Skype software. A number of manufacturers are making phones with a traditional look and feel that work with Skype, for those who don't like headsets.

Skype is a VoIP (Voice over IP) program, which just means making telephone calls over a computer network. VoIP is not a new idea.

Skype has several competitors, but has had huge success with home users due to its reliability, ease-of-use, and great marketing. Like instant messaging, PC-based VoIP programs all have their own way of transmitting data, so users of competing products can't call each other directly. This "lock-in" effect has helped Skype's user base snowball: it currently has 54 million members around the world, and is adding approximately 150,000 more each day.

I have used Skype for nine months, and have found the software to be easy-to-use and polished. Quality is excellent for Skype-to-Skype calls, and SkypeOut calls are good value but the quality is variable. I have experienced some "spim" and "spit" (spam over instant messaging and spam over Internet telephony) through the service, but it has been inoffensive and is easily blocked by only accepting calls from your known contacts.

Skype has its critics. One concern is that Skype can act as a server for other people's calls, passing their voice data through your computer en route to its destination. Some users have reported that their bandwidth and CPU usage has increased dramatically when running Skype (even when not making calls).

This technology is called peer-to-peer (or P2P), and is integral to Skype's success, having been used to great effect in file-sharing applications such as Kazaa (which was created by the people behind Skype). It is possible for your computer to act as a "supernode" and help route Skype traffic, but the software is designed to keep this bandwidth use low.

If you use dialup or have a metered Internet connection, a network monitoring application like NetLimiter may help you control bandwidth usage from all your programs.

Others have security concerns. Privacy is well taken care of as all calls are encrypted, but Skype is a popular application and is sure to attract hackers' attention. Their track-record on security has been good, however, with Secunia reporting only one vulnerability, which has been fixed. Compare this with 85 advisories for Internet Explorer, of which 19 are unpatched. As an Internet user, security should be important to you, so make sure your regimen includes a personal firewall, up-to-date anti-virus and anti-spyware, and regular software patches, at a minimum.

Skype is a useful, free, and well-made piece of software. You have much to gain from trying it.

Links

Skype
http://www.skype.com

Instant Messengers with Voice: Comparison
http://reviews.cnet.com/4520-9237_7-6243313.html

VoIP Service Providers
http://www.fiercevoip.com/links/voip_products_services.asp