Hi Oliver,
No Follow links do not leak link juice but there is a new concept in SEO called co-citation. Basically Google and other search engines are using mentions (semantics) http://moz.com/blog/prediction-anchor-text-is-dying-and-will-be-replaced-by-cocitation-whiteboard-friday to determine how to rank your website. I suspect this is Google's effort to try and reduce spam and the linkbuilding business. The more mentions you get the better your website will rank and especially if the website has authority
Thanks
Carla