How can I create the blurring effect in a video like this?
There are no filters applied there.  It's pretty much basic shots, probably from a DSLR based on the feel of the video.  The shots with the one guy were shot with things overexposed and then they upped the contrast to try and do recovery, but it results in large overblown highlights where there was too much light to fit in the dynamic range (the amount of variation between brightest and darkest spot) that the camera could capture.  It otherwise all looks like standard footage though, nothing special done other than basic color grading.

Note that if you are talking about the shifting blur effect, that's called rack focus and is so apparent because of the use of a fast lens with a short depth of field.  It looks remarkably similar to footage I get with my 5D Mark iii and 24-70mm f/2.8 L lens.

Rack Focus can either be from out of focus completely to focus on a particular subject or from one subject to another. It generally uses a narrow depth of field and a follow focus may be used to help reach the focus points exactly and in a controlled manner.

The technique is often used either to introduce a subject from a dream or stunned like state (for example, if someone is waking up or in an accident, their pov might start out with a rack focus from being completely out of focus). It is also very frequently used to shift the viewer's focus from one subject to another in a dramatic way. In the more artistic sense, it can also be used to simply explore the depth of the scene by moving the viewer through the space.