I found a very useful Firefox plugin from ”Blank Canvas”, that enables your GMail to have HTML signatures. Because it is a Firefox plugin, I thought it might work in Flock, and sure enough, it does. Once you install it from this page on Blank Canvas’ site, and restart your browser, you can create your signature in GMail’s Compose window. This had been a GreaseMonkey script but the author converted it to a Firefox plugin. Thank you, Blank Canvas for a very useful tool.