Selecting "blind carbon copy" or "carbon copy" can make a big difference for an e-mail message — at least that's what celebrity photo agency Retna discovered when they sent out a message to more than 250 contributors in January to alert them of a simple address change.

After receiving the e-mail, recipients hit reply all with their complaints about the photo agency, and discovered that other Retna contributors were experiencing the same problems. That is, that the agency is failing to report sales, pay royalties, or respond to calls and e-mails from frustrated contributors.

Some contributors have protested that they are not even certain how much the stock site owes them, as the online tracking system is so hard to use, and the company is so far behind in payments.

Retna has not denied the complaints, responding a week after the fact with a statement that many of the grievances were legitimate and those they were due to poor management.