For the last ten months or so I've been working essentially full time on a webapp. The webapp doesn't make much money (through donations it covers hosting costs and allows me to go out to lunch daily). I'm not bitter about it. I knew it wouldn't be profitable, but it was a labor of love and I plan to continue maintaining it when I get a job.
Would it be alright to list this under professional experience? I mean, I learned a ton, and the site is live and has a decent userbase.
It seems to me that if the app covers its costs and lets you buy lunch 5 times a week, that's profitable (and a lot better than most apps). I would include it on your resume, since personal projects are a huge indicator that you can work and learn independently, and actually enjoy doing it.
Where to put it on the resume depends on what job you're applying to, your locale, and how successful the side-project was. If it was all you were working on during a period of time, I would definitely include it alongside other jobs. If it was a side project that was big and profitable, I would probably include it alongside other jobs. A side project that is bringing in a few lunches a week might be better put under a "personal/open source projects" category after your work experience so to not detract or distract from the sort of experience you're focused on selling.
Of course you should list it as professional experience. You worked full time on it, it has a user-base, and most importantly it is live and operational.
The level of profitability is not important and doesn't need to be brought to the forefront, especially since you had no expectation that it would be profitable. The fact that it exists and is self-sustaining suggests that it could become a valuable asset. 10 man-months is a relatively short time anyway.
At the very least, you could think of it as a "portfolio" piece and a springboard for useful discussion about business.
Would you fail to list a full time employer that you worked for years on the basis that they went bankrupt and never made a profit while you were there?
If you've been working on it full time, you've put a lot into it and have hopefully learned a lot. Not only is it experience, it is something that they can look at to see your work. Include it.
