Prelude stands more for a chapter of the game. This is a evolving game , this is so both in done mechanics (code) as in the story and inventions we discover as time goos by.
the game official launch date is 15-mar-2011 , the original date was 1-mar-2011 but was set back a little due to some not foreseen server issues. currently they are being tested and fixed.
There is no player cap (like what developer would stop paying players eh)