I take it you're actually making money out of it or you wouldn't have grown it up to 200 blogs, right?
The Sni.pr strategy is all about getting each site to do between $1 and $15 per day.. It's just a numbers game really which is why @Pooomba has over 200 sites in the system.
It's easier to build 200 sites that make $200 combined than make 1 site that makes $200 itself.. (personal belief ofcourse