A few months after having created a little tool to manage shared expenses, one of my roommates who just doesn't like computers, asked me if she could use the tool to settle accounts after holidays with some friends. I was delighted that she understood that the tool could be extended to that usage and thought that if she preferred to use such a tool rather than a piece of paper, others might also do.
Finally, I have an opportunity to make something with my skills that is at least useful, even if it's unsignificant and absolutely not exciting.
Geek section
The first task was to choose the technology I will use to build who owes whom. I was sure to use GWT but didn't know for the server part. At that time, cloud computing and scalability were in the air. And that was also the time Google AppEngine appeared.
I chose that technology rather than traditional JEE and Amazon cloud for one main reason : it is free. Plus it is Google and I like and Google ; plus it is based on Python and I like Python.
If it had not been for the price, it would have been stupid to choose AppEngine: you're kind of tied to Google because of the datastore (archiving or moving you data to another place would be a pain in the ass), and more important, you waste a lot of time to bind Python and Java, whereas it's one of the attributes of GWT's power : you can share code between the client and the server.