Last Updated May 24, 2007 10:08 AM EDT
In short, it's a thoroughly impressive service, though not without a few quirks (like the inconvenient pop-up contact browser, which should be baked in and omnipresent). Big Contacts offers plans starting at $12 per month, but you can get a free account that supports two users, 500 contacts, and 500MB of storage. While you're at it, check out Highrise, a similar service with a spiffier interface. Even if you don't want to replace your current contact manager, you can use one of these services as a Web-accessible offsite backup.