Fortunately, in the UPL this hasn't been much of a problem. Aside from the guy in our league who picked all Red Sox players in March and then sat back and did nothing as his team has coasted to first, everyone else in our league seems to at least still be putting forth some effort in making roster moves.
Over at RotoAuthority, Tim Dierkes has made a list of 8 ways to avoid teams quitting your fantasy league. Here they are from Tim :
1. Make it a keeper league. This is a pretty obvious way to ensure everyone maintains interest in the league all year long. Just like in real baseball, the lousy out-of-contention teams can trade off expensive stars for affordable youngsters. This is more easily done if the draft is auction rather than snake draft style. The more keepers you allow, the more flexibility for poor teams to stockpile prospects. My league allows a healthy ten keepers.
2. Require a decent cash buy-in, and give prizes for the first three or four finishers. I suggest at least a $60 buy-in. Then you've got $720 to work with. $460 for first place, $200 for second, third gets their money back. Even if the first place team runs away with it, you might have a gaggle of teams fighting for second and third.
3. Give cash prizes to monthly winners. If your provider tracks leaders by month, you can dole out small cash prizes ($20 maybe) based on that. The previous incarnation of Fanball used to accomodate monthly stats; I'm not sure if any services do now. Monthly prizes can provide a little extra incentive.
4. Choose head-to-head over rotisserie style. I am not a fan of H2H leagues. A standard roto league already has plenty of luck involved, but with H2H you are slicing up the season 26 times into weekly matchups. I acknowledge that H2H has its own strategies, and it can certainly keep a person invested just for bragging rights over another team.
5. Kick out the worst four teams each year. If you've got enough people vying to be in the league, you can give the boot to x number of teams at the bottom of the standings while keeping the rest for next year. If it's the bottom four, this might create a battle to stay out of 9th place. We are trying this in the RotoAuthority league this year.
6. Periodically publicize the league results, with trash talk. This has worked well in one of my H2H leagues. Weekly matchup results are analyzed on a blog, and losers are good-naturedly insulted. Plus, it's always good to randomly mock a league member for a bad drop or trade. They'll remember that, and strive to prevent future embarrassments. Public shaming is useful, but be aware that trash talk can very easily cross the line and create animosity.
7. Don't play in a league with strangers. For your league, try to recruit friends, family members, coworkers, or other acquaintances. If you see league members in person regularly, they might feel ashamed about quitting on the league. If you join a random Yahoo league, people will have no such qualms.
8. Seek out league members who aren't always busy. The number one reason people give for quitting on a fantasy league is that they just didn't have time to manage their roster. Some people are truly busy, while others just pretend to be. It's a lot easier to say this than to admit they drafted a lousy team and lost interest. When possible, opt for people with a little time on their hands - college students, freelancers, coworkers at a laid-back job, retirees. If a prospective owner never has time to hang out because of work/family/whatever, they probably won't have time for a fantasy league either.These all seem pretty reasonable to me. Although, I imagine most people would have difficulty finding a league that actually kicks out the bottom 4 each time. It seems that would be difficult to replenish every year.