Hi Susan,
To the best of my knowledge, you can’t integrate a twitter feed into Elluminate. However, I have heard of many instances where a “back-channel” was set-up (by participants or conference organizers) so that individuals could interact there during live sessions. Back-channel conversations took place in Twitter and/or Facebook. These conversations were tagged, aggregated, and available from a central conference website.
I've also heard of simultaneous back channel converations going on in Skype and wikis being opened on the fly during live sessions in order for participants to collaborate on presentation related content. The wiki was then linked to the conference website.Hope this helps.