The "You know that thing where" page is titled around the idea that the person posting the trope idea needs help gathering a title or examples for the trope ("You know that thing where this happens? What should we call that?"), but it's currently used as a general vetting procedure for all new trope ideas, even ones where the person posting the idea already has a good title in mind and a number of examples. It can also be used for works and indexes.
The pmwiki part in any URL on this site. TV Tropes used to use an early version of PmWiki code, but has been developed and rewritten to the point where it is entirely separate.
In the title bar, you can see an older title for the site, "Television Tropes and Idioms". Idioms don't tend to get talked about here at all- in fact, idioms would qualify as Stock Phrases, whose creation on the wiki is now actively disallowed. (Though, some more obscure trope names may count as idioms themselves.)
In a perfect metacoincidence, the artifactuality of "TV Tropes" has led to the name of this very trope becoming an artifact in that was originally conceived to refer to titles of TV shows. It fit as we moved out toward other narrative works. But now we also have a page of real-life examples that includes not only things with proper names like places and companies but common nouns like "ketchup" and verbs like "paging" someone or "taping" video.
dennogumi.org was once a fansite about Cyber Team in Akihabara (Akihabara Denno Gumi). The webmaster then converted the domain into his personal blog in which he writes primarily about Linux and pratically nothing about said anime.
When Fiveminute.net was first created, it was called Five-Minute Voyager because the only fivers were of episodes of Star Trek: Voyager. As the years went on and the scope increased, there were occasional efforts to rename. Even after the site moved to a new domain under its current title you'll still find more people calling it 5MV than 5M.net.
deviantART: The Media Watch Dogs are hitting the site so hard that it's no longer "deviant". Also features a Group system where groups might not be art related.
And this has led several people to switch over to FurAffinity, despite the fact that they don't even draw furry art.
Anime Feet is a blog, about, well Anime Feet (Of girls, that is). It soon drifted to more of "Animated Feet" as it included Avatar: The Last Airbender or Justice League Unlimited, though that was still somewhat close to the original idea (Especially since the former is animesque), moreso compared to.... COSPLAYER FEET, which aren't even animated at all! And while some did cosplay as anime characters, there was stuff such as Lara Croft or even an Original Character. The cosplaying wasn't an one-off thing, it was the only thing posted for one month (During which the page had the subtitle "Cosplayers rule!", almost lampshading its decay). They even had another month dedicated to the actresses of the Harry Potter movies, which couldn't get further from anime if they tried. One wonders why they just don't change their name to "Female Feet", as outside the top banner there's been barely any anime feet whatsoever in a long time. To be exact, for the eight first months of 2011 they only had TWO updates featuring actual anime feet, and none by the site owner himself. In fact, the owner doesn't seem to care much about the artifact-ness, as in an update he said cheerfully he now posted a large variety of female feet from various mediums and while he listed stuff like film or comic books, he didn't list anime. (Well, it was included as part of "various animated feet", but the fact he couldn't even mention it standalone despite being the blog's name is kinda sad).