Use of arbitrary HTML in Gmail signature block.

If you have been wondering about when Google will get around to accepting arbitrary HTML in Gmail signature blocks, look no more! There is a published solution, on the web, but with one constraint: 

You have to use Firefox as your browser. A web developer named Chris Pollock has made that publicly available as a Firefox add-on.

 
I have started using it, and love it. Don't you relish the ubiquity, and hence the shareable characteristic, of the Internet?