I haven't tested out Lively yet, since I'm running Ubuntu and it only supports Windows at the moment. In one of their blog posts however we can gather that Lively is well integrated with the Web. They have widgets that allows visitors - with Lively software installed - to jump into a Lively room embedded in a webpage.
I'm wondering if Google will offer the same level of integration with their Lively 3D world. Would make fun Mashups.