The hidden domain in this case happens to be www.microsoft.com. Could Google be slighting their arch rival by hiding their domain name with the ellipsis? I had to hover my mouse over the link and look in the lower-right corner in Firefox to see what the website was. The reason is that the entire URL is too long so Google uses the ellipsis to shorten the path. However, I've never seen Google replace the domain name with an ellipsis - it's always some part of the path.
In fact, I just double-checked now and I see plenty of other links in the search results and in all cases a part of the path was replaced with an ellipsis and not the domain name. Below is an example if what Google typically does when shortening a URL with an ellipsis. Look at the second link with the domain name thesource.ofallevil.com. How apropos.
