A webmaster reported in a Google Webmaster Help thread that in his Google Webmaster Tools Keyword report, he noticed that Google is displaying a blank line as one of his more popular keywords used within the site.
The blank line is [_______________] and he has no idea why it shows up not just once, but twice. The first one is in the second most popular keyword used on the site and the second one is the eleventh most popular keyword used on the site. If you think about it, the underline or line is weird, but even if it technically was a keyword, wouldn't it be the same keyword (i.e. only show up once in the keyword list)?
In any event, the webmaster posted a screen shot in the thread - because honestly, I thought he was on crack or something. Here it is:
Why is this showing up? No idea! In fact, if you search for the line using a site command, nothing comes up.
Forum discussion at Google Webmaster Help.