Claim check: if Apple patented rounded corners, Google patented linked documents
fosspatents.com
fosspatents.com
As an aside, BT did claim to have a patent on hyperlinking.
(http://news.bbc.co.uk/1/hi/in_depth/sci_tech/2000/dot_life/1...)
(http://www.telegraph.co.uk/finance/newsbysector/mediatechnol...)