Facebook provided insight on just how much regrowth the games ecosystem has seen in the last year during a whiteboard session on social games today at its headquarters.

First, Facebook’s Sean Ryan said that games are seeing 30 to 40 percent clickthrough rate on notifications. He did not state how low CTR fell for games on Notifications before the relaunch at the end of August, but recall that this was one of the channels Facebook temporarily restricted for social game developers because there had been too much spam.

Second, Alex Shultz from Facebook’s user growth team explained how his team joined Ryan’s 10 months ago to begin updating games’ approach to accessing and retaining users. Since the two have joined forces, we have seen newer games from developers other than those in the top 10 see success.

Finally, by encouraging developers to explore new genres on Facebook in the last 12 months, the category distribution has shifted from sims games and the occasional casual game to an explosion of casual and casino games. Note that more than half of games on Facebook are still simulation — and the strategy category hasn’t changed much despite Kixeye’s much-publicized success with the genre.

Looking ahead, Facebook still has hurdles to jump in user acquisition costs and discoverability — and it has to jump them on mobile, too, as that’s where most game developers are headed. App Center has some promise; the social network said earlier this month that 220 million people have visited App Center. Users who discover apps there are 40 percent more likely to return to the app the next day compared to the old Apps and Games dashboard. Perhaps more promising is Facebook’s mobile ad product, which could drive more mobile game installs for Facebook-enabled games.

Earlier this week, CEO Mark Zuckerberg said the games ecosystem as a whole was growing, though not as much as he would like. Payments revenue from social game giant Zynga dropped 20 percent for Facebook compared to Q3 2011, but revenues from other game developers increased 40 percent over the last year.

The original version of this story can be read in full on our sister site, Inside Social Games.