I've given versions of the same talk three times over the past three weeks, and wanted to take a moment to note (mostly for myself) some observations I've had about both my own presentation and public speaking in general.
First, I'm pleasantly surprised at how little nervousness I've felt. I've done a bit of public speaking in the past year or two, and in former lives have held jobs that required me to do somewhat better than commanding a room, but the past month's events have been less personal and had a higher chance of impacting my career - and still I've gone into them feeling more or less comfortable. Certainly some portion of this is my familiarity with the subject matter (my talk is not entirely a review of things I've written about on my blog, but there's a lot of overlap), but I dare say that I might also be growing into myself a bit. I recognize that this is kind of a weird thing to say of oneself, but I'm pretty sure it's at least partially true.
I think some part of my degree of comfort has to do with the fact that I've found a way of balancing my own deeply held philosophy with the fact that I'm selling something that speaks to that philosophy. This has been a long time coming, and probably deserves more than I can grant it here, so I'll leave it at that and move on.
I will note, however, that the entire experience of speaking at an event is noticeably more exhausting than simply attending. I suppose this is self evident, but presenting your work & thoughts is de facto an invitation for people to ask questions of you (and present their own work & thoughts one-on-one), and responding to that attention takes considerably energy. That's not to say that I don't enjoy it; indeed, eliciting a response is the primary reason to speak publicly in the first place. But it drains me a bit too - and I'll admit that I still haven't followed up on all of the business cards I've collected this month.
Lastly: I've also seen quite a few other folks speak publicly over the past month (conferences are conferences, after all), and I can't help but wonder what I would think of my own talk. If anyone out there has seen me speak recently and has feedback, send it along :)