I love the fact that more and more devices are sporting built-in Wi-Fi—the Sony PSP, smartphones, even Kodak’s EasyShare-One digital camera. The lone hitch: Wi-Fi is useless without a hotspot. Sure, thousands of spots are available, but few are free, and coverage is far from ubiquitous. What if you could marry the short-range power of Wi-Fi with the huge coverage areas of high-speed cellular services such as EV-DO to create a portable hotspot?

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.