I thought I had solved the problem described below, but a reader told me the gray box was still appearing after my fix.

Yesterday, a reader reported a bizarre gray box containing an ad covering a large part of this blog. There seemed to be no way to get out of the gray box and back to the blog.

I wasn’t able to replicate the issue with my own computer or browsers, but other testers said they experienced the same thing. Sometimes the gray box contained an ad, sometimes it didn’t. At right is a screenshot of the gray box without an ad (courtesy of tester Bridget Weide Brooks) Sometimes it could be clicked out of, sometimes not. A URL at the bottom of this screenshot, after several redirects, goes to Groupon. Bridget said she saw an Omaha Steaks ad.

I am flummoxed by the hijacking of this blog by this ad. I do not run any ads on the site except Google Adsense ads an one other ad on the Google Affiliate Network. I cannot find any source code that would be responsible for this ad. And since I can’t seem to replicate the issue, I can’t test solutions.

I apologize to readers if you experience the inconvenience of this gray box/ad. You may be able to get to the blog by trying again. Of course, if you are experiencing the gray box, you are probably not reading these words.

Would also appreciate any thoughts from readers who’ve experienced a similar hijacking or have any idea what could be behind it.