We store your email and username. 
We might show ads on some stuff if we ever get approved for adsense. 
We will more likely just try to sell you games. 
We might use an event tracker to understand how you use the site (e.g. mixpanel). 
We might use some analytics stuff to understand our audience (e.g. google analytics). 
Your ad blocker will take care of that stuff if you don't want it.