If each instance is only used by a small number of users, it might not easily be identified, since the exchange of the platforms wouldn't be visible to Turkey's censors.
I don't think this really helps as a means of suppressing information. Unless you block everything, the information will get out and once it's out of the region, you no longer have control. I believe it's mostly about soldiers carrying their cellphones around, posting on facebook when they are idle etc, and you don't want troop movements and staging grounds to be quite that public. "Hey guys, please no Facebook" doesn't work at a large scale, blocking those sites is much easier.
I don't think this really helps as a means of suppressing information. Unless you block everything, the information will get out and once it's out of the region, you no longer have control. I believe it's mostly about soldiers carrying their cellphones around, posting on facebook when they are idle etc, and you don't want troop movements and staging grounds to be quite that public. "Hey guys, please no Facebook" doesn't work at a large scale, blocking those sites is much easier.