@dagobert: Generally I've found just reconnecting to the server has given me more kerbals to play with in Career mode, however the fact the 'story line' contracts, other than the first three, only seem to be doable once per server rather than once per play made if very hard for players to get enough money to do anything. So it's not the only issue you'll face. Currently I play in science mode with other people on my server, gives some progression at least. As far as I'm aware ore generation isn't the same for each player either which will lead to problems with shared mining outputs later on.