As someone who takes notes as an attention-focusing device, I used to take notebooks to conferences. These days I tend to be seen at conferences with a laptop, typing away. For an example, the first four entries in this blog of mine here on HASTAC were my notes from presentations and discussions that I attended at the HASTAC Conference in early 2007 in Durham NC.
In one of his online projects the Cool Tools blog, Kevin Kelly posted a link to Tips for Conference Bloggers, a six-page PDF of advice for liveblogging at conferences. I found much of this PDF useful advice.