There are plenty of answers in this Q&A, so you might want to try the search box on top right in addition to the answers here.
I would like to point you this question first:
Is it common for people to work for free in exchange for equity in a startup?
In addition I see some issues with what you wrote:
- You wrote your team which is around 23 has marketing capabilities. Why could they not recruit developers? Recruiting today is about marketing your company
- You wrote your team has some snazzy ideas. But is that all? Nobody builds application after an "idea". There needs to be functional design (mockups), usecase diagrams, business plans and so on. Of course this is just an Q&A, but if you would write me an e-mail like you wrote this question, I would not take you serious (I am a dev)
That being said, I am not sure if your company would attract me. What have you tried to change this?
You asked for developers to work for free and get money when the project is successful. Your team has a size of 23. If I do a rough calculation and add the complexity behind social web apps I would guess we are speaking of man years of work - full time. If you consider that you basically ask somebody to work for - lets say - at least one year for free with the hope that it turns out "pretty well". And after that year he might get a 1/23 from the revenue. Not really promising. You would need to become a second Facebook to attract me, but this is unlikely.
The same goes for the equity. You ask for lots of work and give a developer some equity. It would be 4,16% if everybody gets the same. Not promising, for that amount of work.
If you want a developer who does that in his spare time (or maybe sacrifices holidays or so) you need to offer some more than that. Basically, from your Question above I can see you plan a "social web app". This does not impress many people these days. I don't know the exact idea, but it is most likely a $x for $y idea: a Facebook for Dogfriends (or something like that).
You must know that many developers get many offers like that regularly. Many people have ideas to improve Facebook, G+ and so on. But the risk of coding that is simply to high: to much work. It is complex.
Maybe I am wrong and your idea is great and fantastic. Then please tell the developer what your team of 23 person does after the implementation happened.
After all it turns out to one thing: if you don't pay a developer, you'll get exactly that quality. A developer has ideas himself. If a dev codes for free for the ideas of somebody else he will not spend much time. If something unseen happens (better project, better idea, wife becomes pregnant) he will simply leave. Devs usually don't like to take over others work. The second dev probably declines because he cannot agree with the messy style of the first. And so on.
Suggestion: pay somebody.
If you have 23 people on board and you pay 80$ for the dev (not sure about the US prices) everybody would need to pay around 3,50$ for the developer. This would mean 550$ for every participant. This is totally acceptable if you all believe in this idea. And it is a full pay for the developer.
Probably some of your team will now say they drop off because it is to expensive and they don't believe in the project. Why should then the dev do?
Anyway, you could ask the developer to get a better equity and only paid the half of his standard price. This would make 250$ for every team member and share holder.
I bet, if there is money in game your recruiting - if done with a great marketing - will probably be more successful.
If you are still not convinced now... you can always try to outsource. In Russia you can get a developer for 2000€ a month. At odesk.com you can get people who are at a rate for 15$ the hour. But please be aware: outsourcing always brings problems. It can work great, of course.