The little "Chat with Marty" module on the left side of my website is a cool little widget I got from Google. It allows visitors to your website to chat with you without revealing your google talk name, or requiring them to add you.

You can get the widget from here: http://www.google.com/talk/service/badge/New

Update: I removed the chat widget after getting quite a few interruptions during my work day.  Word of advice, use with caution.