Selected answers from the Dumb SEO Questions G+ community.
Paul Thompson: That`s your homepage with a URL parameter added by a referrer spammer. The fact that the parameter (the part after the "?") is an actual URL is designed to trick you into visiting that URL. Such visits pollute your data but otherwise do no harm.
Victoria Walsh: That`s reassuring Paul thank you so much for your help!
Gerry White: There’s a lot of spammy data in most accs - less so now, but at one point we were talking about a bucket load,