One of the most thoughtful sessions of the conference so far was Julie Leung's presentation on Blogging as a Social Tool. There's more info on her blog at http://www.julieleung.com/.
Julie talked about the principles that she has developed for deciding what to blog about (and not to blog about). She did a great job using personal stories to explain how you can balance the goals of maintaing some personal privacy with the benefits of connecting with people locally and far away. There might be slides coming on the Gnomedex site, but it was the kind of presentation that you definitely want to see in person--keep an eye out for this one at future conferences.