“What signals can that be sending to Internet Explorer users?”
Well put by Neowin.net. Read the article. Internet Explorer is going down, baby!
IE is a conglommeration of code built on last, last generation code is pretty much the problem. Firefox is new, efficient, fast, and has 1,000 times less the security issues as IE (but that’s mostly because virus and adware writers and hackeres write their stuff for IE).