BrightTALK is an organization that is supposed to be a media company providing technology webinars you can watch. The problem is they are one of the most obnoxious spammers on the planet. If your email addresse gets on one of their lists, you are screwed! Their unsubscribe options do not work and seem to actually sign you up for more SPAM from them. The only way to deal with them is to reject their email and protect everyone in your organization. I do this by creating a rule in Exchange online.
I highly recommend everyone to add this rule to their mail server settings. After an hour of creating this rule, I have already blocked over a dozen emails from these bastards.