I'm going to split test it on a new site soon, have no idea if it will have a positive effect on sign ups. What do you reckon? I'll do a post on the results, either way!

My prediction: it'll have a positive effect on sign ups, but retention will be lower.

You are probably right. I've made a 'hideAfter' option, so it can maybe do 2 or 3 small nudges then disappear, so as to initially draw the eye to a CTA. Although by default it's set to annoying mode :-)

or it just moves bounces to a different page

I'd click the button just to make the arrow go away