14 of the top 25 Facebook games lost monthly active users over the course of March, as we covered at the beginning of April. This was, more than anything else, the result of Facebook removing third-party notifications early that month — a communication channel that many developers relied on to keep players returning.

Developers saw even bigger slumps in April. MAU losses were tremendous across the board. 18 of the current Top 25 experienced a decline, with other factors, like Facebook platform performance issues, also contributing to the problem.

Nevertheless, the industry trudges forward, as five new games also make their appearances on the Top 25 this month — including the tremendously fast growing Zynga app, Treasure Isle. It’s not clear if those apps, or any growing smaller ones, are just gaining users so through cross-game promotions and advertising, or if there is also new organic growth starting to happen.

> Continue reading on Inside Social Games.