Which chess website has the strongest players? The debate on which is the "best" chess website tends to be subjective and thus is inconclusive. On the other hand, the site that has the strongest players should be objectively ascertainable provided metrics are available.

So which is the strongest chess website in terms of:


Number of registered titled players (FM, WFM, IM, WIM, GM, WGM)
Number of active (routinely visit) titled players 
Number of super-GMs (> 2800)
Or other verifiable metrics.
ICC and playchess.com are definitely the top two in terms of the number of registered titled players who play actively.

I was able to find metrics on how many titled players are on ICC, seen here; I couldn't find the numbers for playchess, however they are similar.  Many titled players play on both.