Talk about virtually, almost everything. This blogosphere, is essentially almost everything that people uses on the web wide world.
To blog is to share anything random. May it be videos, photos, writings, etc. And the internet is just about sharing all that, connecting, gaining, and working.
Websites or blogs that shares videos, there is also this thing that called Vlogs; youtube, vimeo, dailymotion, tudou, etc. Also sites that shares and connects with people that blog about photos, and so Photo blogs; instagram, flickr, pinterest, photobucket, etc. Of course literature blogs and everything in between.