Another possibility: how many people would be willing to donate a few bucks a month to support it? Call it the public radio model. You won't get rich, but you might pay for upkeep and servers.
Donations are extremely difficult to make work. I tried it after getting decent traction in 2009 and didn't receive a single donation to cover server expenses. I'm guessing with Patreon things have gotten a bit easier but for a business I would highly advise against going down the donations route. In general, small payments also tend to take up a disproportionate amount of your support time compared to larger transactions so you have to be prepared to deal w/ that.
One big difference post-Patreon is that I no longer think "my small regular contribution is just going to get chewed up in transaction fees", since Patreon does just one transaction a month and then divides it up among several people/organizations that I support.
But, it would not be my first business model to try, just an alternative to "we built it but now let's just shut it off".
