couple of interesting bits on pinkbike thought i might as well link it.
better than the usual dribble.

http://www.pinkbike.com/news/To-the-Point-Cartridge-Bearings-2013.html

http://www.pinkbike.com/news/The-Assembly-of-a-KS-Lev-Seatpost-2012.html

I now understand the difference between a regular radial bearing and an angular contact one after reading the first article.