I have accounts on odesk/freelancer and think that is necessary to have a pre-screening of jobs descriptions. For example, somebody ask for build a "search eng

I have accounts on odesk/freelancer and think that is necessary to have a pre-screening of jobs descriptions. For example, somebody ask for build a "search engine" and have a big budget... but still not clarify enough what mean to him "search engine". So the only option is apply to the job, and wait for the customer to talk about it. Then you wait days, weeks and nothing is answered back. Probably the user get scared? I think that give to potential customers somebody to talk about the project first, to properly describe it (understanding not a full spec, but enough to clarify things in a broad sense) will help a lot. Also, I wonder why this kind of sites not use their own developers to give this. So when a new customer wanna submit a project it pay, for example, US 50 for talk about it before submit or something like that.. (Like a community-driven-facebook-style-lets-talk-before-submit thing)