The online judges I'm talking about are like UVa. http://uva.onlinejudge.org/ People usually use it for ACM-ICPC training. Every Oj I know of can fulfill 1 and 2.

For 3, the innovation is the badge system.

No.4 is nice, it closes the gap between OJ users and employers. That's something OJ's lack.

Topcoder does all of what you told, except a badge system. That's just a small difference. You need something better to compete with Topcoder.

Maybe your platform support more languages? One can't hope to hire lisp programmers from looking though Topcoder's competitions records.

I hope this site become successful. I really don't like Topcoder's interface. xD