WiseStamp is a browser extension that lets users customize their email signatures with their social profiles enabling them to add their latest tweets, blog posts, music, an eBay item or anything they want to advertise. I use it to promote my site, tweets, and my LinkedIn profile. Users may also add custom-made images to make their signatures attention-catching.
Before, it was just an extension (Firefox for me) that works on the browser-side. Now on GMail, including Google Apps domains, WiseStamp is integrated into the email interface. You’ll see a WiseStamp link near your username on the upper right hand side of your page. And when you click it, a window will pop-up to let you customize your WiseStamp signature.
After customizing your signature, try composing an email message. You’ll see your new and shiny WiseStamp signature. If you see your old signature appended to it, configure your GMail settings by removing your old signature.
You may download WiseStamp extension from their site.