I just read an article on Sitepoint about Crowdsourcing for Freelancers. For those who are unfamiliar with the term, crowdsourcing is when you put your project up on a site (99designs, Crowdspring...) and get multiple options for the design. You then pick one and pay for that. I feel that it basically amounts to spec work.
Sitepoint's article basically advocates that you can use the types of sources above to save some money during these tough economic times. Looked at from one perspective they are absolutely correct. By outsourcing some parts of your work to these sites you will save money over what a professional freelance designer could cost you.
Did you really catch what I said there though? How would you feel if your clients decided to go to one of these sources instead of coming to you? If you design logo's you would probably agree that logo design does not cost $5.00. If you agree with the last statement why would you do the same to other designers?
This article also made me think of sites like Elance, that do bidding on freelance projects. Often it seems that the lowest price is the law (to pull from the famous Zellers saying). While it could be a good way to start to build your portfolio I would not encourage anyone to work with any of these sites for very long.
Ultimately if you are willing to crowdsource some of your work don't complain when your clients start to do the same. You already started to devalue the industry and your own profession when you voted with your wallet.