Mibbit has had quite a few mentions in various blogs, and has had many favourable reviews. Here are a few of them.
May 8th 2008 - wired blog (Compiler)
May 5th 2008 - gotgame
May 2nd 2008 - wangtam
April 2008 dinside bloginformatico techiequest civity genbeta ghacks Ajaxian teknobites pirillo appscout KillerStartups LifeHacker mamchenkov blog WidgetsLab WebWorkerDaily UniqueFrequency Mashable france TechBuzz AbhiTech DownloadSquad geekissimo GeekFriendly Mashable Webware puntogeek