This is hott on the interwebz right now and would be a wonderful addon to vb4.
Allowing users to register with either existing facebook* twitter* aim* google* openid* myspace* etc.
If linked with facebook* notifications sent to facebook.
If linked to twitter* give options on a forum thread to TWEET the message based on the account they provided. Could be interesting if it tweeted forum topics with links with every reply they make on a thread.
More contact icons for more networks in postbit.
Just overall better intergration with outside sources would be really fasinating addon and could advertise vb quite a lot.
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