And 3 years later...
I'm posting some news, in case someone stumbles upon this post. It's worth mentioning that the project is first of all not dead, but has in fact evolved
a lot.
The official link =>
Tatoeba : Collecting example sentences
There's now a small community around the project. People have added lots of new sentences (we've reached 400,000 sentences recently, there was 300,000 sentences back then). The project is supporting lots of new languages (a bit more than 50 in total). The website has many more features than back then (I'm not going to get into details).
But the needs haven't changed. We still need people to check and correct sentences. We still need people to translate. We just need people to participate in general.
If you like the idea that you can learn by contributing, please come take a look