The Guild says that “it is unethical to expect trained and qualified professionals to contribute quality content for nothing.”
Furthermore they claim that writing for free undermines the value of journalism and lowers the quality of the work. This makes sense, because people who will write for free are not necessarily the best writers out there or, conversely, they are people (i.e. celebrities) who can afford to write for nothing, which turns publications into platforms for wealthy voices with time on their hands.
Lastly, the Guild points out that the site managers (like Arianna Huffington, who just signed a multi-million dollar deal with AOL) profit off bloggers’ free contributions, which is blatant exploitation.
As a journalist, I am sick of seeing websites advertising on Craigslist that they will “give me exposure” in exchange for my work. Writing, good writing, is skilled labor: it takes time (research, reporting, drafting, and editing); it requires education, experience, and know-how.
If you want free (or dirt-cheap) content, write it yourself.