Florian Kiersch posted on Google+ a new experimental Google search feature baked into the knowledge graph top carousel bar. It is a timeline version, where if you search for something, Google may show you the facts and knowledge of that query over time.

Here are screen shots showing the facts about Google over time in the timeline knowledge graph:

When you mouse over data elements, it will show you the details:

When you click on an element, it would drill deeper into that element.

Here is the Google+ post that has a video from Florian on this feature:

Forum discussion at Google+.