As an employer I have seen a weakness in one very important aspect of your service.
If I want to hire someone say for a web design job they will normally mention some websites which they say they designed. Now it is very difficult to confirm their claims. Because when I write to the contact details provided on the websites most of them do not reply to such emails. Or the replies may come very late.
And most important is they don't have to reply. I can imagine it would cumbersome for them to constantly respond to "Did XXXX listed at Freelancer.com (profile url) make your website?". There's nothing in it for them.
So first do you have an alternative way for employers like myself to verify past work of your freelancers? Do you have anything like "verified profiles" in store?
If not, the I would like to table my suggestion. That you modify your website such that while creating and updating their profiles freelancers must submit any websites they claim to have worked in a special data field which you check in the back-end and confirm with website owner what they are saying is true.
Or make it such that when responding to Requests for bids from us employers, any website URL they provide must be entered in a special data field (not the general message area). And this data field once submitted runs a verification check against your database to confirm it's truly a website recognized as past work of the freelancer.
Because anyone can list any website url and say "Hey look, this is my work!"