I'll do my best. You are correct in that you maintain a part of your roster from year to year. I've been in keepers where you were allowed to keep anywhere between 2 to 8 players so it varies depending on what the league decides. The main added dimension is that you have a chance to build your team over several years which can affect how you draft, trade, and use the waiver wire. Guys like Justin Verlander, Francisco Liriano, and Hanley Ramirez got drafted higher in keeper than non-keeper leagues because of their potential a few years down the road. So in that sense it's a little more like real baseball. The key to a keeper league and really all leagues is that if you can find a quality group of people who will stick together, it can be really fun. You might not win this year but you can always start building for next year. Easily the best site I have found for joining quality fantasy baseball leagues is
www.fantasybaseballcafe.com Go to "Forums" and look in the classified section. There is also a lot of intelligent baseball and fantasy baseball discussion there...and some not so intelligent. Good luck