Keep track of your friends' submissions on various competitive websites (Codeforces, Codechef, Spoj, HackerEarth, HackerRank - suggestions for more are accepted).
It has a lot of other features ?
1. Streak notifier
2. Search a problem by tag. (Yes you got it right - across all the above mentioned sites)
3. We got a list of trending problems both globally and also amongst your friends.
4. A global leaderboard along with a unique rating which includes submissions from all the websites.
5. A list of upcoming contests and an option to remind you 30 mins before the contest starts.
6. Do you often remember some friend's submission on a particular site and want to view/download that submission - we got you just what you need.
The goal is to keep people motivated in algorithmic programming and solve more and more problems.
Facebook page - https://www.fb.com/stopstalkcommunity
Github - https://github.com/stopstalk/stopstalk-deployment (Yes production code)