Every group of friends has that one person to go to for tech advice: what kind of TV to buy, the right HTML tags to pimp out a MySpace page, and so on. Believe me, I would know. But although I consider myself fairly willing to share the tech wealth, my powers pale in comparison with the sage wisdom dispersed in the "Ask a Geek" feature found in each issue of Popular Science.

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A: Tagging is the act of assigning your own keywords to things online—photos, blog entries, bookmarks—so that you can easily categorize, locate, and share them in the future. One of the best examples is del.icio.us, which lets you save Web bookmarks to a page on the site instead of to a file stashed away on your computer. This way, you can access them from anywhere and let other people see what sites you like.

A: As my mama once told me, there’s no such thing as a completely free iPod. But in this case, she may have been wrong.

Many of the sites in question—FreeiPods.com, FreePSPs.com, FreeDesktopPCs.com, FreeFlatScreens.com—come from one company, Gratis Network, which has earned a reputation as being fairly legit by actually giving away thousands of free items. So what’s the catch?