So you're the kind of guy that logs into his favorite wiki if he sees a mistake here, a trope to add there, a wiki link somewhere else, an opinion even. Small, efficient, clean edits.
And then there's this guy. He writes an entire article or post from scratch, does it on word or on his own little wiki or clean pad site located far from your view. He'll spend hours polishing it, copy-pasting it here, but not submitting, just previewing it, marveling at it, and then, if tonight he's too tired, post it tomorrow. Or in a week. Or whenever he thinks it's ready, or just has time. This is the [[TitleDrop Trope Dropper]]. (Or [[TheWikiRule Wiki Dropper]], Forum Dropper, FanFic Dropper etc)
It doesn't just happen on TVTropes, or wikis in general. It's rare on forums or such, however, because it's a fluid discussion and you might want to write your reply fast before the flames go too high, burn out and you're staring at a screen telling you that you can't post on that thread and go to sleep crying because you couldn't post your precious ... er-hem, OrSoIHeard. [[AndZoidberg Oh and]] [[CaptainObvious you're expected to do this]] when posting FanFic.
This practice comes from the primordial time of the internet, when connections were short and expensive, and writing in a forum, or a mail, with your crappy "reliable" IE and the thing not being sent, would guarantee the loss of data and [[BrickJoke staring]] at a White Screen Of Despair. Or you'd write this and later go to a friend who had any internet whatsoever.
Presently the need for this has diminished, as now we're led to believe a lot more people have cheap, reliable, fast internet connections and time on your hands, with the world becoming "smaller" and changes in any page in which you and a group who would contribute, becoming faster and sometimes sliding off track before you get to say your bit. Other needs have appeared however, such as posting through a proxy (it's hard to find a good one, and when you do, you want to make the best of it).
Not to be confused with TitleDrop or [[ProfessionalKiller the guy that makes a career]] [[DarthWiki/ThatTroper out of "dropping" Tropers]].
Also, you guessed it, SelfDemonstratingArticle.