There’s a new initiative from the various industry groups involved in email marketing.
These include the Better Business Bureau, American Advertising Federation and Direct Marketing Association amongst others.

This includes an opt-out website and an “advertising option icon” that websites can display to indicate they subscribe to the recommended practices.

I think this is an effort to deal with the increasing nervousness about spam and hackers and the fact that it can be hard to tell the good guys from the bad guys. That has contributed to decreasing effectiveness of “newsletter sign-up” type offers on websites – or anything that requires a consumer to give a website their email address.
Whether this new effort takes hold – or is effective – remains to be seen.