TV Tropes is a wiki that catalogs the variety of devices based on shared understanding or experience, called tropes, used in storytelling to quickly get an idea across to an audience. The site started with tropes used in television, but it has since expanded to cover all storytelling media, including fanfic and web originals such as the PPC. It is known for being highly addictive thanks to the abundance of shiny, tempting links on any given page.
TV Tropes and the PPC Edit
The PPC is not affiliated with TV Tropes in any way, but there is a Protectors of the Plot Continuum article on the site. Lots of PPCers now find their way to the community from TVT.
Back in the old days, most PPCers tended to arrive by way of fanfiction.net and/or the various OFUs, particularly the first one, OFUM. This meant that for the most part they came armed with certain foreknowledge of fanfiction in general and some specific fandom and OFU humor, particularly based on The Lord of the Rings, from which fandom sprang both the Original Series and OFUM. Since the Original Series got kicked off ff.net, and fewer (if any) PPCers post their missions there now, and not as many OFUs are active, few people arrive that way anymore.
This means that much of that foreknowledge is often missing—many tropers have never written fanfiction themselves, for instance, and not all arrive having read the Original Series, or OFUM, which is close to the top of the PPC's recommended reading list. Furthermore, the PPC uses unique definitions of some terms, such as "Mary Sue," which has sometimes led to confusion. It has added up to a paradigm shift in the community, which is not bad in and of itself, but which has met with some resistance from older Boarders who miss the days of being able to curse Toey and reliably expect ninety percent of their fellow-Boarders to get it. Some of this shift is evident in the much broader spread of fandoms covered in PPC missions, and also in the appearance of materials written by older members specifically intended to educate new members about the PPC community and its history, how it works, and how it doesn't work, which had not been considered necessary before.
The TV Tropes Editing Spree Edit
There is an unfortunate history of animosity between some PPCers and the TV Tropes admins, who took issue with a group of PPCers working to unbias and broaden the representation of the PPC on the site. For some time, it had been based heavily on the edits of Laburnum and Tawaki, whose spin-offs are generally regarded as a bit on the fringe: Laburnum tends to take on squickier badfic than most others, and Agent Tawaki ended his career as a were-penguin Borg Time Lord. Since their edits mainly focused on their own spin-offs, and they were the most active at it, people who were finding the PPC through TVT were showing up with a distorted idea of what to expect from the group. There was a series of incidents resulting from new members misguidedly focusing on trying to out-squick each other with the content of fanfics rather than the quality, or making agents of ever more exotic and powerful species, both of which are very bad ideas in the PPC (see YKINMK and PPC Badfic).
A group of PPCers therefore got together to go through the tropes on the PPC's article and its mentions on the various trope articles. Each one was evaluated for its relevance to the PPC as a whole, and if found relevant, was edited to give more general and/or more iconic examples when necessary, with a focus on the Original Series and other widely known spin-offs or missions. However, the TVT admins ultimately accused the PPCers of "whitewashing" and undid many of the changes, and even banned at least one PPCer at the forefront of making the desired edits. This does not sit well with the folks involved.
All that said, however, tropers are welcome in the PPC community—heck, they comprise a lot of it nowadays. PPCers have put a lot of effort into making it easier for new members to acclimatize (see the FAQ and other help links above), and that's purely because we want to foster a happy, thriving PPC where everyone can join in the fun without getting hopelessly lost along the way.