I sign them all the time. They're extremely common. While most that I sign are for business writing projects (such as company reports, employee newsletters, etc. where you're dealing with confidential company information and documents that may not be made public), I've signed them for content as well. Sometimes it's just because the client wants ghostwritten work. The entire point of ghostwritten work is that the client can claim authorship. If you give that right away, you can't be claiming authorship anywhere else without their expressed permission. Another example was more temporary, where the content was for a new site being launched by a large company - they didn't want information about the new site getting out before it launched. As to why someone would agree to that, it's simple in my case at least: I make significantly more money when I give those extra rights to clients (depending on the length of the piece, it can be as much as an extra $.25 / word). Not everything has to be included in a portfolio, so it wouldn't make sense not to occasionally take on those projects when I earn much more for them. That's one of the reasons I repeatedly tell people when setting rates to know what rights they're giving away and to not be afraid to charge more when they're losing more. It's up to a writer to decide what they want in return for giving up rights to use something in a portfolio - whether that be more money, or giving up temporary rights to talk about it in order to have a bigger company in that portfolio down the road. What they need to understand is that they don't automatically have the right to claim authorship in ghostwriting situations, and they have to carefully review their terms of the project with the client to see what they are, and aren't, allowed to say. Jenn