My browser's security function is reporting that a segment of the chat archive has malware inserted into it. What could/should I do as an RPG.SE citizen?
There was an image in one of the chat messages that was hosted on a domain that Chrome flags as a possible malware distributor. The image was now a "404 not found" image anyway, so I've just deleted that message. The image filename was "doublefacepalm21.jpg", so I can imagine what it originally contained :)
As soon as I deleted the message, Chrome stopped flagging the page.
As to your question what you should do: Precisely what you did – post here on meta (or on https://meta.stackoverflow.com/). Thanks!