I’ve attended many Hypertext conferences in the past, and have spent a number of years at UofT, so it’s a double pleasure to point out that the Hypertext 2010 conference will be held at the University of Toronto June 13-16. The conference will cover topics including social computing, adaptive hypermedia, and hypertext in education and communication. The deadline for submission in January 18, 2010. For more info, please see the CFP.
I am also happy to note a number of old friends from Toronto in the organizing committee, including my adviser, Mark Chignell, as the general chair, Elaine Toms as Program Chair, classmates Rick Bodner and Harumi Takeshita as Treasurer and Local Arrangements chairs, and Rick Kopak (Adaptive Hypertex track chair) and Jamie Blustein (Workshops) as well.
The hashtag for this conference is #ht2010, and the conference twitter account is @ht2010. There are also LinkedIn, Facebook, and other social media pages associated with the conference. There is even a SlideShare page for uploading presentations. I assume you do have to have your paper accepted first.