Many freelancers are concerned about retaining their rights. I really don't care about the rights to the items I freelance. (Which is a good thing since I can't retain my rights and work on Guru.) The thing that puzzles me about this is that traditionally published author's frequently give up their rights to the work. Go to the library and randomly choose five books off the shelves - look at the copyright page. Most of the time you are going to see a publishing company owns those rights not the author.
Now, this is shifting somewhat, but not necessarily for the better. Traditional publishing companies may make you file for the copyright, but then make you sign a contract that gives them unlimited use. Since they want you to market yourself, can you really expect them to pay to have the book copyrighted?
Anyway, the things I care about, I self-publish. There are, for example, plenty of freelance jobs asking people to write romance novels. I could do this, but I do not. I am not going to put that much time, effort, and thought into something that will be published by a probably mediocre publishing company and if promoted right may end up making them tons of money. It doesn't appeal. I can do that much myself, and I do with CreateSpace.
But there are tons of jobs that I really do not care about. Website content - I won't even take these unless I can't find something else or the topic is easy and interesting. Research papers - I am not daring enough to approach the peer-pressure (uh, I mean peer-review) community on my own at this time. Articles - I put them out in about 1 - 2 hours, not enough time to make me interested in putting my name on them most of the time.
I am not a good marketer. I am struggling through self-publishing and starting to see my business pick up, but I do not do everything I should be doing to make my business shine. And, for the most part, I focus on editing and giving people feedback on their manuscripts. I love helping others, not asking them to buy my work - trying to justify its value. So, I am a freelance writer. And I give my rights away because I don't really want them. But that's just my opinion.
If one of my book-length fiction works had been traditionally published, I would have fought tooth and nail to retain only movie rights.