I use wickr to buy weed. Never been a problem, since it's just as anonymous as pidgin. Only difference is the encryption.

Privacy online, is not possible at all. - You can make it harder for the government, but once it's online, it's online. No matter what you do, there's always a way to crack it. (Same with your house. You can put all the locks on it you want, but I have a lockpicking set, might take me a while, but I'll get in at some point.)