I don't know why websites do that. Did you really think I was going to accidentally view the text of that popover? Nope, all I remember seeing as I searched for "X" or "Close" is a lot of white space where one of those two buttons should have been. My eyes never cast their gaze beyond the extreme edges of that popover.
I have to agree. This was a particularly irritating popover, and the means to close it was virtually invisible. It took me a while to find it.
I think that with the advent of the almost universal use of adblock, websites have become more aggressive in seeking revenue by other means. Popovers have become much more pervasive, even over the last year. They are going to be harder to kill than pop-ups since they make viewing the web page conditional on a deliberate action by the user.
