It turns out that the page has been included by our ad serving company for a few of technical reasons that I won't bore you with (suffice to say it's supposed to be helpful, although it didn't really turn out that way in this case). Unfortunately they spring things like this on me sometimes and I don't hear about it until folks start complaining.
So there is a legit reason for the page to appear, but the fact that it was suddenly appearing a lot, and didn't contain much information about what it was for, obviously caused some confusion and consternation.
I had a chat with them about it today though, and after checking it out they realized that they had a bug at their end which was causing the page to appear *far too frequently*. The timing checks out -- the bug was inadvertently introduced at the end of last week during a code push, which is when the problem started happening here on DU. We're weren't the only site who had this problem over the past week.
Fortunately they believe they've been able to resolve the problem. With the system working properly, DUers should rarely if ever see this page (apparently it's been active for two months, but it's only been over the last few days that it started bothering everybody). So we're going to keep the function for now, because it is doing something useful behind the scenes, but hopefully you won't see it again -- or if you do, certainly nowhere near as often as before.
If however the problem is ongoing for you, please let me know as soon as possible because I want to make sure it gets resolved.