Should you have linked to this post after your Classified Ad was deleted and your description field consisted out of a single line of text, do not reply asking why it was deleted, but read through the following carefully and compare.

Please allow me to start by showing an actual (resent) example posting in Classified Ads:

'Project Name:
*removed*

Description:
My project is a Knight's Age RPG were anyone can do a variety of things like mining,have a house,learn magic,etc...

Project Goal:
Make an RPG that's free for anyone were they can do what they whant.

Skills Needed:
I need help with icons,codes,and all, i did a part of the game but the project it's to big for me.

Compensation:
The team will get Admin or GM depending on the work and will get access to all of the game things.

Contact Information:
Anyone can contact-me in my mail or instant message that is: *removed*

Sorry for the bad english.'

All this advert displays to potential customers and future employees is that the one seeking a team won't even put forth effort and time in creating a half decent post. How could you imagine that this would change when confronted with the task of designing and creating a game, something that easily consumes hundreds of man-hours?
What the advert should mention already begins with such essential information as the basic game style (Isometric/Top-view, Turn-based/Real time, On the map battles/Battle-Screen, Singleplayer/Multiplayer), followed by the games' unique selling proposition (yes, players are going to need a real reason to play your game instead of the thousand other clones out there). But that's only the very start. Describe the battle system in detail (detail means not just a few keywords, or a single line of text), elaborate on skill progression and how magic influences and interacts with your environment. Are the non player characters in your game going to be dumb minions that spend all their life waiting for interaction on a single place, or are you going to strive for more?
The better your reader can envision the project, the easier the decision if they want to be a part of this dream and the higher the quality of possible replies.
The general rule of thumb would be that the second somebody got to ask you for any further details, your advert already failed.

And this is only for the advert seeking assistance!
As a programmer or artist, you're often confronted with the phrase 'I've all planned it out in my head'. That's great, but no use for anybody else, unless somebody actually develops a mind reading device.
The first step of a designer is to write your concept down. Everything. In detail!
Don't get me wrong, I'm not talking about the strange two pages design documents with a couple of keywords thrown at you, but a real design document, which can easily get in the hundreds of pages for a half decent game.
The profit you get is incredible. Not only do you really have to rethink your design in detail while writing it out (and you'll be astonished how often you shake your head over ideas you had), but your employees won't have to assume, or ask you for every little decision forever on. Which already implicitly explains how detailed a design document should be, as the programmer acting on it should never have to ask a single question. Whatever the player should be able to do, whichever choice she can take and whatever consequences arise, it has to be outlined (see functional specifications).

If you take the time and effort to actually meet these requirements, you are a valuable assert to any team.
It's just that hardly anybody ever does around this community, which resulted in the misconception that you meet everywhere.

Edit:
I feared that I might come off as too negative, but I decided against it, so I'll add on a bit more of the tricky parts where a lot of people stumble around design.

Frequently, you're going to see a reference to a feature implementation in another game (e.g 'we want to create a Final Fantasy XII battle system), or a TV show/film/Manga/story. As descriptive as this may be, it is bad for two reasons. First of all, not everybody played the games you played, so you restrict yourself on potential help. And, even worse, it is likely that you didn't put enough thought into this feature, or rather why your game would benefit from it's implementation. A game should be fun to play, but a random mixture of features and functionality isn't automatically going to be fun, even if each single feature might have benefits, they would have to interact and harmonize, in order work out in a game. If a game you love lacks this feature, there might very well be a reason that the developers didn't want to implement it.

And to everybody (like me, I'm very guilty and bad here as well) who tries to write part of the design document in actual pseudo code, or even worse real code, that's bad. The programmer(s) should translate your proper English into the language your compiler can understand and interpret, which is tricky enough. If you can not explain your design in real English, you haven't put enough thought into it. Which is true the other way round as well. A programmer worth the money (if you're going to offer a real compensation other than 'GM') should always be capable of translating her work back into proper English again. This can lead to funny consequences as you can see in a recent posting on the developer forum. When you translate the code snippet that was shown there back into English, you'd get something along the lines of... 'Get a reference to this tile. Get a reference to the same tile again. Compile a list of tiles between these two tiles (the tile and itself, logically resulting in a list containing this single tile again). Now, for every tile in that list, take this action.' As one might guess, the real solution should have looked a bit different, like 'Get a reference to a tile fulfilling these specifics. If such a tile exists, take this action, else report the failure'.