Beginner, just like it says, these games are designed for beginner roleplayers. People new to the game, who do not have a lot of experience. These games are generally designed to be easier to understand, simpler concepts and plot lines that aren't overly complicated, that don't intimidate users who are not used to things like: multiple story lines, multiple plants/countries/locations running parallel to each other, or playing multiple characters. The demand for intricate, complicated characters is less too. In short simpler character designs. Everything a beginner needs to feel comfortable and at easy within a roleplaying environment.
Intermediate, these games are designed for players who have been in the game a while or are more comfortable with more complicated designs. Intermediate is a middle ground, and because it is some intermediate games are more geared in favor to users coming from the beginner roleplays, while other intermediate games are geared towards users who have more experience and are edging towards advanced games. This said in general the plots for intermediate games are more complicated, you often have chances to play multiple characters, larger worlds, and you'll find more finely defined worlds, races, and details. Again, as I said this is the middle ground so depending on the host the game may be geared to one or the other end of the spectrum.
Advanced, these games are for those players who have been in the roleplaying game a while. Most advanced games have complicated, overlapping worlds and story lines, multiple characters, higher character design expectations, and player involvement (such as players being included in the development, design, and building of entire worlds, races, and cultures on top of the expectation of designing their individual characters and posting in the game.) Advance games often touch on multiple parallel running story lines, and in many cases are large scale games that involve multiple environments (worlds, races, cultures). Many advance games have combat system, or magic system, and in general are very intricately designed. They really are for very experienced players.
None of these groups are based on paragraph count. The WTFRPG community, in general, avoids the use of the commonly adhered to paragraph paradigm. Most games players are expected to write what they deem necessary to convey an idea, move a plot forward, and be interesting. You'll notice in most games players write any number of paragraphs and there is no minimum or maximum expectation (in some games there can be a moderate to extreme difference in paragraphs written from post to post). On the other hand, some games do have specific expectations, you simply need to read over the game to know what is expected of you.
This brings me to one last point. Some beginner games, players may write a lot, and in some advance games you'll notice they don't write a lot (or in most cases it varies). So when it comes to choosing a game you need to read the overview of each RP, see what the host expects of their players, see if you like the plot, the design of the game, and if you're even interested in it. All the games have their merits, it's really mostly about finding something you can get into and be part of and REALLY ENJOY! So just see what is out there.
I hope you aren't searching based on paragraph count, you may find it hard to do here.
Here is what the sites owners say each rating is:
What is the minimum amount of experience you looking for in a player?
“Beginner” suggests you are looking for a player of any level of skill, from someone who just decided to pick it up today, to someone who’s been playing in forum rpgs for 10+ years, and played table-top games for 10+ years before that.
“Intermediate” suggests you’re not looking for someone who just started, but it’s not really important to you how much experience they’ve had so far as long as they’ve got the basic ideas down and have decent role-playing skills.
“Advanced” suggests you’re looking for players with a good deal of experience and a high degree of writing skills. It is highly suggested that if you choose “Advanced” that you are equally advanced. You will put off players if your own writing skills are Intermediate or Beginner and you say you’re looking for “Advanced” players.
You might like to clarify what you’re looking for in a player in the sections below.
Which are a little different from what I said . . . though, I feel what I said is equally as valid an assessment . . . either way.
HERE IS A GOOD PLACE TO GET STARTED, to help learn the site a little.
edit: Guess I want to add "a high degree of writing skills" doesn't have anything to do with paragraph count . . . guess the real thing is paragraph count just ain't a big thing here, hopefully (really, I do hope it isn't somewhat that is leaking into the community, I would be so sad, but now I'm projecting . . . move on, sorry.)
---------- Post added at 06:34 PM ---------- Previous post was at 06:28 PM ----------

Originally Posted by
Xavirne
If I may, might I suggest you give this a look-see? I think that might help you get a better grip on those terms and see that we're all a bit at a loss for what they truly mean.
Actually, that is a TERRIBLE thread to link to . . . that thread is actually a debate, one I brought over from Gaia a while ago. The "literacy levels" there are the paradigm I mentioned. We, or at least I seriously HOPE TO BABY JESUS, do not adhere to them here. I would not base your knowledge on the content of that thread. Feel free to debate the paradigm and usage of the terms. Otherwise, just go off of what I said above.