Population estimates after some more crafting, more basic sheet metal, and a server change from being on too long, then being logged out.  what happened?  I don't know.  I wondered if the population numbers would change?  from searching the player register i got an average of 3-10 players or 6.5 players per page.  For 30 pages times a maximum permutation of 15 results a page, a 1.4% active players per three letter permutation.  Those are players who are online at any given moment. 
There are some 17500+ three letter permutations when searching the player register.   Of those 1.4% will be active.  450 players per search. and 1.4% of that is:   6.5 players. then multiply that by 17500 permutations of three letter search terms for ta-da-da-da: 113,400 players active at any one time.  My sample size is small.  Less than 20 but more than 10 searches.  So the confidence level is likely around +/- 20,000 players.  Just a guess.  This is but one of many ways to gauge the active population on entropia, particularly Calypso.  With such a population and active auctions and private trade, Calypso's peds flow greatly day after day, week after week, pull after pull.  Be part of and enjoy your time on Calypso.