Depends, do you think there is someone you could sell it to? 12,000,000 sounds like it's got a big audience is the domain memorable, etc? Would you develop it or sell it... etc. etc. etc.
the combo of cc and 3 words in the domain probably will make it hard to promote. Look for short word combos that you can redirect to that domain - to build more traffic and make it more popular. It's really hard to tell, also depends on what web segment you're trying to target..
Overture doesn't distinguish between singular and plural searches, and it also adds a few "related searches" as well so the numbers isn't always 100% correct (to say the least...)