I keep a red and silver fob on my key ring. It's a bit longer and skinnier than the remote-entry clicker for my car, holds 32 megabytes of data, and can exchange information with just about any computer. More than once, I've been saved from a tight spot because I had a copy of a critical file, such as a PowerPoint presentation, on the fob in my pocket.
These USB keys, so called because they plug into a computer's universal serial bus port, have been around for a while. But prices have fallen by half in the past year, and the devices are learning tricks that could take them well beyond their current role as replacements for the floppy disk.
Basic memory keys, available in a variety of shapes and styles, are essentially commodity products. You can buy a 32-MB key for less than $20, or spend more than $500 for a 2-gigabyte version. As a cheaper alternative, there's the bulkier Digitalway MPIO HS100, which uses a teensy hard-disk drive instead of flash-memory chips, and offers 1.5 GB for $200. When you slide the key into any Macintosh or a PC running Windows XP, 2000, or Me, it will show up after a minute or so on the desktop or in My Computer. (Windows 98 requires the installation of software first; Windows NT doesn't support USB.)
The only important difference among the basic storage keys is whether they use the original USB technology or the newer and slightly more expensive USB 2.0 version, which permits much faster data transfer. The 2.0 designs will work in older ports at the original speed. However, they draw more power and may not work in some extension ports, such as those often found on keyboards.
THE LATEST BATCH OF MEMORY keys do a lot more than store data passively. The best of them automatically run certain applications as soon as you plug them into a Windows PC. A good example is the Migo from Forward Solutions (www.4migo.com), starting at about $115 for a 128-MB version. Say that you want the PC you use at home to look and function as much as possible like your computer in the office. You plug a Migo into your office PC, and a program in the device automatically starts to copy Outlook folders that you have selected, such as mail, contacts, and calendar. It can also store settings such as your desktop wallpaper and Internet Explorer favorites.
Now plug the Migo into your home PC and log on. As long as you have Outlook and the other desired programs running on both PCs, the little device will quickly create a semblance of your office machine, including the mail that was in your office in-box. I found that it worked well with standard Internet mail accounts. But corporate mail using Microsoft Exchange required some fiddling with settings to get Outlook to work. And think twice before using it on the PC of a friend or colleague: Their original settings won't necessarily be restored when you pull the Migo out.
Other keys make enhanced security a sales point. Most manufacturers offer versions that password-protect your data. But I especially liked the EasyTrust from M-Systems, whose products are usually sold under such brands as Iomega and Hewlett-Packard. It offers encrypted data and a lot of convenience: When you plug it into a computer you have designated as "trusted," you don't have to enter a password.
In the future, these data-storage devices may acquire additional uses. One that I would like to see is a password-protected and encrypted key that would store user name and password information for all the networks, mail accounts, and Web sites that I log in to. When plugged into a computer, it would intercept the login requests and supply the correct information. Another would be a key that could actually boot a computer to make a borrowed PC really look and act like your own machine. This is technically possible on Macs and the newest PCs, though the size of today's operating systems and licensing restrictions make it impractical. But even without such advanced features, these memory keys are so handy that just about everyone should have one. By Stephen H. Wildstrom