Wassup?

So, this evening I find something new when I pop up on the site, a black "toolbar" across the top of each page. Most of it isn't functional (for me at least) or meaningless. It does have some kind of logout clickspot, and if I knew what it would log me out of I might try it. However, these days I lean towards the "don't f**k with anything unless you know what you are doing" option.

So, is anybody else seeing this thing or know what's going on? The Luddite in me just wants it to go away.