Brabblr is a meta tool for your "cat blogs" like Twitter and Jaiku. It's currently in private beta, but I've gone ahead and gotten a sneak peek for you.
With this meta tool, you can add updates to all of your Twitter-like blogs. Brabblr supports Twitter, Jaiku, Frazr, Wamadu and Textln. Brabblr works in the same manner as Twitter and the rest, and gives you the option of receiving updates from your friends or recent updates from the entire community. Each update indicates where it came from, which lets me know that Brabblr should be importing updates from the other sites it connects to, but this feature seems to show that all updates are coming via Brabblr instead of their respective sites.
Other than browsing through the site's recent updates, there's not really any other way to find and befriend other Brabblr members. And unless the import update feature actually becomes a better part of the site, Brabblr won't be the Twitter hub it hopes to become. There's a great potential in becoming a hub for this type of service, though, as several sites have incorporated a feed function that ties in with Twitter.