Zoominfo -- a company that has created some sort of business contact database where you (you probably being "spammer") can buy lists of email addresses. Ken Magill talks about them here , quoting deliverability consultant Laura Atkins at length . Here's my take …
Word on the street is, if you're running an MTA that utilizes pipelining aggressively, you're probably having trouble sending email to Gmail right now. Here's an example of the error message received when messages are being deferred: (host aspmx.l.google.com[72.14…