Just a word of warning: if you're sick of F2P discussions, you might want to skip this one.
That said, these discussions usually focus on whether F2P is its own game or if it's a demo for membership. The question "What is F2P?" is never asked. People that support additions to F2P usually claim that it is its own game, citing Mark Gerhard's statement of the topic from early 2009, while those that are against it state that Jagex is a business and should avoid doing anything that would discourage players from subscribing.
Few people state that the free version of the game is just that: the free version - something wholly different from traditional game demos, where you are limited to a small portion of the game for a set amount of time, or from completely free games, which are usually supported by optional microtransactions. Instead, RuneScape uses the "freemium" model, where players can play a limited version of the game for as long as they'd like or pay to be able to access everything. As the fact that the model has a name would suggest, RuneScape is not the only program to use it. Virus scanners, music streaming and online radio, and other games do the same.
In fact, several of the faults that players attribute to RuneScape's free game exist in other freemium programs: ads for the premium version, content limits, and the like. As the model relies on players subscribing, this makes sense, and those who are opposed to updates to the free game will be quick to remind others of that fact. The ads in particular are a necessity, similar to ads on a television show: They keep it free. That doesn't mean that Jagex can do anything to the free game and justify it with "It's free". Look at any number of good television shows that were brought down due to mistakes that appeared silly in hindsight.
Does this make F2P a demo? Not entirely. Both demos and freemium games accomplish the same thing: they get potential players interested in the full version. Demos do not, however, let players play for as long or as much as they want without pressure to buy outside of the occasional ad. Players can, and often will, stick to the free version, which is why RuneScape (and other products) has a population of 'pure F2P' players. You can't fault them for it any more than you can fault a fan of a TV series for watching reruns of his or her favorite show on television instead of buying the season on DVD. One fan pays by watching ads and the other pays directly and gets more content out of it.
This means that both sides of the F2P argument have their merits: while the game is its own game rather than a demo, it's also supported by ads for the premium version. Even if it wasn't, there is nothing to stop players from remaining 'pure' F2P aside from the many reminders about how much greener the grass is supposed to be on the members' end of things. There's also nothing that will make Jagex add new free content, or stop adding content to it.
It also means that this article will probably offend both groups, so that they'll finally have something to agree on. That's progress, right?