Hey @thepostit, welcome to Syrinscape! glad your enjoying it
We do send out newsletters but one of the best ways to keep appraised is here on the forum. We’ve got a great active community so you will get to hear about new sets and pick up lots of really useful tips on how to get the most out of the app!
With regards to how often we release content, take a look at our 2017 Release Schedule. As you can see we have lots of new stuff coming out this year and there’s definitely a creepy Cthulhu theme going on