I don't know that there's a need for a call-to-action, unless you are advertising for Digg. Digg is a good site. If you like it, then read and post there. Over time, the site will bias more towards the conservative end of the spectrum.
I have no personal stake or interest in Digg except I think it's an interesting site some Freepers may not have heard of. I wasn't advocating leaving FR in favor of Digg... simply using Digg as another tool, which some may be in favor of.