This morning I received emails from the forum containing attachments. It was strange but I realized what occurred. The OP who made a new post, included a google doc link. Gmail users automatically see google doc files as attachments in their emails.
What's concerning is that, while Gmail scans these docs files for malware, there could be remote code hidden that remains undetected, or any number of advanced attacks through this mechanism. And users receiving an email from the forum may be more likely to click the attachment. I'm not sure what the potential fix is, but just wanted to give people a heads up that this type of attachment could reach anyone's inbox who is watching a subforum or thread and gets email alerts.