Monetizing a webapp

I am building a website that solves word games (scrabble, wordfeud, angry words etc.). It does it better than any websites I have seen.

I am thinking about how to make money on it (I have three children) - I've thought about putting Google AdWords banners or paypal "buy me a cup of coffee" or even convert it into an app for the Apple app store.

How could a service like this be successful, or should I just settle with it as another of my "toy projects"?

The site is still in beta and currently hosted at appharbor.

As far as ads:

1. Use Google Insights for Search to see if a lot of people search for keywords relevant to what you're offering (eg. "scrabble cheat", etc.). If so, pick a few popular keyword combos that you think people trying to find your site would search for.
2. Run those keywords through the Google Adwords Keyword Tool to gauge how difficult it will be to get ranked for your keywords.
3. If everything looks good so far, pick 2-3 phrases or keywords to optimize your site for. Make the keywords central to your site's copy, speed up your site as much as possible, get links from relevant sites to your site, use social media to build traffic, etc. I would wait until you have some decent traffic (generally speaking around 10k+ visitors/day) to roll out ads. Otherwise, they will slow down your site and drive away some users while making you chump change. With solid traffic, the passive income from ads can be enough to live on.