As a freelance writer, I've done a lot and learned a lot over the years. From content mills, to independent service want ads, outsourcing, contract agreements, freelance gigs, copywriting work, and bidding, it seems I've done it all. Bid sites were particularly sticky for me. For writers who want to build a solid portfolio, further their career, and make serious money, I would not recommend it.
What are Job Bidding Sites?If you step back and take a closer look, you'll notice that firms like media companies, ad agencies, and in-house agencies are not particularly posting jobs on these sites. Most of the folks on there are typically looking for the best copywriter at the cheapest rate. Add the fact that other writers are on there competing for that job and it's a recipe for disaster.
Oftentimes, you have to lower your rates just to beat the next guy. Even then you may not even get the bid! Plus you've spent valuable time proposing your services to a job you may or may not get. Also, let us not forget that many of these sites may charge a "quote fee" or "transaction fee" if you do get the job. Elance charges over 8% of your agreed upon fee payment.