It lacks access to Firefox's vast collection of add-ons, but if your time online centers around social networking, Flock's browser may already have precisely the features you need.

The Flock browser is designed to manage one's ever-expanding presence on social networks such as Facebook, MySpace, Flickr, and Twitter, along with more traditional online conduits such as Yahoo Mail and Gmail. The software's available for Windows, Mac OS X and Linux; for now only English users have a 2.0 version available for download, but there are currently 15 international versions of the previous 1.2.6 edition.

Our installation experience was normative. On first startup, the software requests sign-on information for whichever of over 20 services you choose to manage through the browser. Once that information's in place, the browser automatically queries each service and keeps you abreast of mail, messages, all your friends' status updates, photos, the Digg cavalcade, and so on.

Since it's built on Firefox, it shares the important Firefox key combinations, and import of Firefox bookmarks, cookies and passwords was seamless. (Import support for IE is also available.) But if you're attached to various Firefox add-ons and themes or even those for the older version of Flock, the new version's going to hurt your feelings. Earlier versions of Flock themes aren't yet available for the 2.0 version; the site says that they'll be updated eventually. At press time, meanwhile, just two extensions were available -- Me.dium, a friend-tracking application, and the self-explanatory Screenshot.

Our testing was delayed for several days while the world waited for a Twitter-related fix to the browser; Flock's support staff did a decent job of keeping users posted on the support forums, which appear to be well-monitored. We tested the browser's ability to track Digg, Facebook, Flickr, Myspace, as well as Twitter, plus e-mail accounts on Google and Yahoo. Flock juggled our feeds gracefully; we saw no evidence that messages weren't reaching us even via the notoriously flaky Twitter, and our options for updating our own accounts were straightforward, since as a last resort the sites for the various systems are just a click and a tab away. We experienced one (deliberate) crash, and the browser recovered all our tabs and settings perfectly.

If there's any problem with Flock, it's that it doesn't take into account that some of us still use the Web for tasks other than social networking. Tabs are clear enough, but a plug-in allowing multicolored tabs (a la Firefox's ColorfulTabs) would make them easier to keep organized; same goes for multiple rows of tabs a la the indispensable Tab Mix Plus. Users can currently scroll their open tabs from side to side, but frankly it's not the same.

More significantly, the social-network monitoring mojo in Flock is so central to its appeal that having an important network missing is annoying. The option to monitor my BetaNews e-mail account would have been nice, but it's the absence of LinkedIn support that really got on our nerves. But the version is young, and it's no small thing to stand just a few add-ons away from social networking nirvana.