There are two brackets or "wings" on the socket. They must be fastened to the casing by gluing or pressing/heating or something. The socket itself doesn't need to be glued.
Unless solder is "red-colored", then its glued to the board, along with (4) small soldering points via its (4) legs. There is nothing keeping the socket "connected" to the walls of the case, if its not touching it.
I took my 900 apart after my port came out, and again, its a very flimsy installation/solution. No bracing whatsoever, only its connection to the board.
Best thing is to be careful when plugging/unplugging. I don't know if such problems will be avoidable but at least careful handling will prolong the use. I assume after the one year Nokia warranty you will have to pay for this to be fixed?
I was taken to task by one person for blogging on this subject, but I believe it was warranted (note: I would have taken a different approach if I were still a NOkia employee). This is indeed a design flaw.
The "cheapness" of the connector is not an issue as go1dfish points out. They're all cheap in cost. It was the choice. Original connector was surface mount with no retainer flange. I recommend through hole mount with a flange.