Google has just released Google Talkabout, a funky little widget to put on your blog so your readers can chat directly to you via Google Talk. No doubt a product of their 20% time policy.
I have a penchant for gadgety things, so I've added one to my blog (scroll down a bit, above the disclaimer).
The usefulness of it is completely debatable of course, considering I usually don't even have time to chat to my friends on Google Talk. But go ahead and give it a try if you happen to be loitering around here :)