mid xx
"free dating" does enjoy having 1.2M google searches; people looking for a free match-making site
and you have a lot of end-users to shop to, and online match-making is a hot online industry
but i have to disagree with you when it comes to the point you make for seo/indexing. having "free dating" in the domain does help when you're going after "free dating" searches, but having those numbers after does hurt it. why would freedating100 be anymore helpful to indexing than freedating1200, or any other combo of numbers
so you'd have to shop this domain to an end-user on the premise of brandability/memorability.. but you're going to need to come up with a better concept of what the "100" stands for