Summary: Pirate101 is an MMO that's aimed at kids, but fun for all.
Pros: Piratey goodness that just happens to be appropriate for all ages. Tactical combat works surprisingly well in the pirate setting. Full of oft-requested MMORPG features like ship combat, companions and housing.
Cons: Combat can be slow when other players jump in during battles. Only a fraction of the content is actually free.