I just want to say that public worlds get a bad rap in these forums. I used to be one of the people who looked down on public worlds until I was convinced by an owner I like and respect very much (pstrnutbag44) to take over an abandonment. I then won a World Series with the team, which gave me no choice but to re-up the next season.
Now, that world, Clarkson, has the best blog in HBD (seriously, the Clarkson Chronicle, by cactusmaz is truly outstanding) and a developing core of young owners who are learning the game from ethical, interested veterans. Foxx, which has a 50+ page thread in this forum dedicated to it's problems, has also been an outstanding experience thanks to tropicana & the others from the original rescue crew's efforts to drain the cesspool and fix the problems.
I wish more veteran owners would join public worlds - en masse - and then help enforce ethical, honest game play while teaching new HBD owners how much fun this game can be. Private worlds certainly have their perks - however, all but a few are riddled with similar issues that public worlds get dumped on for (i.e. aliases, trade rape, super teams). And while it's always sad to see a 3rd season owner announce "I've been invited to join Private World X - see ya!" it's also gratifying because all private worlds (especially those occupied by the snootiest of private world players) need "young" owners to replace their 1 or 2 every few seasons.
Playing in public worlds is also good for me as a member of the Mentor Program (tecwrg deserves everyone's thanks for starting this); I'm doing less 1-on-1 and much more group work - I know which 5 new owners are asking questions and interested and getting better. That helps me when private world commishes ask "hey, what about X?" when they are looking to fill open slots.