So the guy figured out that browsers render all links on a page and then reflow any that should by styled to indicate they have already been visited. Apparently you can figure out which links have been reflowed by checking the number of frames that have to be rendered to display a link. Not a big deal, and if your site uses the same style for links that are already visited, not an actual attack vector.
The second attack, using SVG (or, I assume) canvas to create a screenshot of what's visible to the end user could be leveraged for an actual attack, you know, if everyone didn't put iframe busting code on their pages served over SSL. Vendors can update the SVG rendering system to adhere to the same cross domain restrictions as other components and not include pixels from iframes in the buffer that is available to inspect via JS and this hole will be closed.
Not too much to worry about here, but I'm surprised that SVG doesn't already do this (canvas won't allow JS to work with cross-domain images unless they have been served with a header that marks them as "safe" according to their originating service).