Is the edge open or is it in the middle of the geometry. You can only extrude open edges. Well... technically you can extrude a closed edge in "edit Mesh" but it orphans the newly extruded part when the mesh is converted to edit poly. In general extruding non-open edges is a mess...
To open rendering options, LMB the mesh when you're not in painting mode. Open DynaMask on your folder or layer, then open the Material IDs rollout. Click the Links button. CTRL+LMB each masked area you'd like to add to your current mask. That should do it. :)
Apparently anyone with a google account can join, but only when Google open the doors. They opened sign ups last night, but they must have hit their limit. There's probably a twitter account, or their blog you can subscribe to, to stay up to date with them opening it up again.
for some odd reason i can't open anything bigger than what i have now or else maya will crash. I can open 4 mil in zbrush, and 2 mil in 3dcoat.. but my maya will not allow me to open anything higher than a million.