Firefox- the new tabs are no longer blank pages, but a history

This just started happening a couple of days ago and I haven't seen anyone mention it. I use firefox and when I click for a new tab, it's no longer a blank page, but a history of where you've been- it's not a complete list, but nine small boxes that tell me I've been to Godlike and 8 other sites. It kind of creeps me out. There is an x to close the boxes, but they just come right back. I know I can clear my history and probably make it go away, but it just feels like another way to tell us that they're watching.