Steam – Meaning of Icon Near SteamPlay Text

I believe the ? means that Steam isn't sure if it's synced with the Steam Cloud. When you launch the game, or if you toggle cloud support for a game, the icon turns from the "question mark" to just a cloud icon. I tested this with a couple of games in my library, and this seemed to be a pattern. I can't find any Steam FAQs on this topic, so this is more of an educated guess backed up by some research.

I presume that on launch, Steam checks in with the cloud servers to see if there's any updated information to sync, and then it "knows" that the data is properly synchronized. At other times, it's possible that it has changed since the last time Steam checked, so it shows the question mark.

According to a moderator on the Steam forums "snooze" is a state automatically applied to users that have been away from their PC for 2 hours or more.

There are other programs that can interface with Steam, and some of these also have the option of manually changing your status to something that is normally not possible to manually set your status to. Therefore, you might find people in the "snooze" state even though they haven't been away that long.