Dive summary:

• A marketer and blogger, Bogomil Shopov, says he was able to buy one million emails for $5 from Facebook and Twitter app developer.
• A similar advertisement for this transaction says 310,000 Twitter users' info is available for $5, too.
• The emails listed in the blogger's screenshot are not all public emails.

From the article:

We asked Facebook for a statement regarding the validity of this alleged user data leak. A Facebook spokesperson told Search Engine Watch: “We have dedicated security engineers and teams that look into and take aggressive action on reports like those raised here. Since this is ongoing, we are not in a position to discuss the investigation at this time.”