Although clay.io is useful for things like online Hi-score boards, there are other benefits, such as the ability to put ads into your games (useful if you plan to make the game free), store analytical data (such as how many times people play the game, read the rules, mute the sound etc) and push your game with ease to other sites such as Facebook, Chrome and Mozilla store. It's quite easy to use, though can bring about a few error messages if you're not careful (these can be easily overcome after a bit of experimenting).
Kongregate is definitely a good site to get your game on, though there is always the danger that it will just get buried or ignored (Gamejolt is another game site worth keeping in mind, though I've only been able to get the desktop version of my game working there as touch controls don't seem to work for some reason). I'm hoping to put Board Horde up on Kongregate tomorrow if I get the chance (I was just waiting to finish my latest update, and get some bugs ironed out first) so I'll let you know any problems I encounter.
Anyway, good luck with everything. I'll be sure to lend a hand whenever possible.