Please add your own questions and I may add them to the FAQ if I think they are a good addition.
I'd urge you all to try ranked teams though -- they are generally a lot better than existing ranked play, even if you aren't that into ranked.
Some I have seen so far:
Q: Why'd you make ranked teams anyway?
A: There are many answers to this, but two that I think are sometimes missed are that we wanted to provide a new version of ranked teams that was both more competitive AND more accessible. On the competitive side, by having a team-based rating, we can have a much better measurement of skill levels, since so much of what makes a player good is their teamwork with specific players.
On the accessible side, by allowing you to have throw-away teams with different groups of friends, we let you show your less good friends how to play ranked well without tanking your rating or any other undesirable downsides.
Q: If I make a 'newb' team with my newb friends, and we do poorly, does this hurt me on my serious teams?
A: Not really. When you start a team, your rating will be partially seeded based upon your past performances -- so if you are from a lot of high rated teams, you'll be seeded higher, and if you are from a lot of low rated teams, you'll be seeded lower. However, since you are one of 5 players setting the rating, it's hard for you to really tank it alone. In the unlikely case where EVERYONE on your team is actually good but plays with a lot of less good players, you'll just have to win another game or two initially to be where you would be otherwise.
It is true that the games will affect your aggregated stats and champion win rates -- but I don't think the effect will be large there, and mostly people care about your maximum rating.
Q: I notice that my team went 3-2 and got ranked, but our rating is well below 1200. What gives?
A: You actually start off at something like 900, and gain bonus points every game, win or lose, that you play. Around 50 games, the average rating should be roughly 1200. We did this to provide better seeding, because teams do need to learn how to play with each other, so we assume that every game you play is marginally improving your team strength up to a point.
How many teams can I be a member of?
I believe it is either 4 or 5 -- not sure what we settled on when we launched.