I like this one best - ads are probably not an option because widgets have limited real estate. To eliminate the deceptive part, just message all yours users f

I like this one best - ads are probably not an option because widgets have limited real estate. To eliminate the deceptive part, just message all yours users first before changing it. Be candid about money issues (ala reddit). Start with just Amazon maybe. "Hey guys, this thing has blown up and we can't afford the hosting cost. To keep it free, we've got to try something. So starting in 1 month, we'll automagically insert our Amazon affiliate code into any tweets than contain an Amazon link. All other links won't be touched. We really didn't want to do this but it is either this or shut down the widget (or start charging for it). Thanks for bearing with us as we run this!" You might lose 10% of freeloaders but this is a good thing.