I would like to know why the rank position looks like "#2648 of 18,495" (it seems that there's only 18,495 members) while only in US I can find more than 60 thousand of them. Who are those 18,495 in the rank position?

Anyone who ever signed up is counted as a member but only those who have played a recent game is counted as a player.

See here for the list of players.

http://www.chess.com/echess/players.html

Look for "View Players" on your Online Chess page. 

 

Thanks, It's ok, although...  may I know what is the period of time for a recent game?

i think you have to play like 10 games to be included in the rank thing. or so that's hwat a staff member ytold me.