I just opened a new gmail account to subscribe to good ol' David Deangelo's Double Your Dating newsletter (for training in email copy, of course, erherrm).
Much to my befuddlement, after signing up 3 or 4 times using various different proxies, cleaning out my cookies, etc, David D's emails just wouldn't turn up in my inbox....
Until I realized that Gmail now comes as default, with 3 different inbox tabs. One for 'Personal' emails, one for 'Social' emails (facebook, google plus etc), and another for 'Promotions'.
David D's emails are no-where to be seen in your inbox, until you click the 'Promotions' tab.
I'm pretty sure that all mass emails are now going to be thrown into the 'Promotions' tab, which no-one will bother to open, UNLESS they are actually looking forward to receiving your emails... which they should be doing anyhow I suppose.