Overall, Q is a military "backchannel" which allows those at the top of our military, along with president trump, to speak directly to the citizens of the world without fear of discovery or media intervention. Its a conversation between the citizens of the world and individuals with beyond top secret security clearance. It is also a means of skirting the laws surrounding "classified" information.

The topics discussed range widely from corruption in America to corruption around the world to child trafficking to national security issues and all sorts of other stuff in between.

No one truly knows who or what Q is for certain. The best guess is that Q is a collective of advanced military intelligence operators with above top secret security clearance. Some have suggested that "Q" in fact refers to Q-level security clearance, possibly based on "the sum of all fears", one movie which Q frequently mentioned, in which one of the characters has a Q level top secret security clearance, if I remember my movies correctly. It might have been the hunt for red October too.

Q does not make predictions. Rather, Q would use his top secret clearance to provide hints about certain things which later, once events played out, would make sense in retrospect but at the time did not necessarily make sense. One major example is the events that took place in Saudi-Arabia with the arrests of the king and other members of the royal family. Prior to these events Q left hints about what was about to take place, either because Q was "in the know" or had reliable surveillance information to back up his claims. However, at the time, no one knew how to interpret these events because they were made in such a round about way that no one could decipher them. Once the events played out and everyone knew what had happened, Q would then confirm how he had been foreshadowing the events and that is how "proofs" were born. People were able to "prove" that Q had in fact provided hints about a major world event before the event had taken place.

So in this regard, Q provided hints as to intel on future events. However he never "predicted" events. Predictions imply you are using imprecise means of fortelling. Q uses Intelligence information. Q doesnt predict whats going to happen, rather he KNOWS whats going to happen.

Predictions then come from the Anons. Anons are everyone else who reads Q posts, the anonymous users of the internet, partucularly the forums which Q posts on. Because we know that Q is supplying intellegence about possible future events, anonymous internet users often make it a game to try to piece together Q's posts to glean information about possible future events. These are predictions, because Q is often very cryptic and trying to predict how the hints Q has provided will translate to future events is very very difficult. And these predictions are almost always spectacularly wrong. But its still fun anyways.

Thus, Q does not make predictions which dont come to pass. Other people make predictions based on clues that Q has provided, which are almost never 100% correct or even close to that.

Q has verified his identity as someone deep in the know in many different ways. First, he has direct access to president trump, based on many different confirmatory tests. Second, he provides information that would be impossible to know unless they had access to beyond top secret information. Third, the coordination of Q would require a lot of high level intelligence work. Forth, Q has implied that they are military intelligence, although that does not necessarily mean that Q was telling the truth.