In the end, it appears not much in the long run. Glenn Greenwald who was the actual person releasing the information Snowden gave to him says (according to himself) he specifically didn't release a lot of the info as he deemed it was too sensitive. We don't know what he didn't release, only that he says he didn't release some things (again no verification on this, his word only).

The information that was released publicly, really didn't have anything that impactful in it, despite what a news show's host may try to scare you with. It described a lot of US (specifically the NSA's) and others surveillance techniques, however, this was already broadly known within the public and defense/intel community, this was just the first time it was "officially" verifiable and contained a lot more details than they would want disclosed. Since the 80s, most of what was revealed was known publicly in the right circles, and wasn't' at all surprising, again but that doesn't make a good news story! In the end, we don't know the direct impact other than the NSA and others needed to make some changes to their strategies

FYI his stuff was NSA not CIA -- very different things.