In 2007 I left my job of 13 years and started my own business. I needed a phone system. I knew of Asterisk only in name, having no real previous experience with any PBX or even VoIP - unless cussing at my friends over Yahoo Messenger while playing Battlefield 1942 counts... which it doesn't. My business partner was looking at a used Merlin system on eBay, but I at least knew that was a terrible idea and asked for a week to come up with a better solution.
Long story short, I downloaded Asterisk and dove in head first. Once I got a couple of softphones working (and had had a pretty good time doing it) I threw caution to the wind, ordered a Digium TDM card to plug a few POTS lines into, and bought a mess of SIP phones for the office. In a couple of days I had a functional phone system working.
While trying to answer some of my own questions along the way, I started hanging out in the #asterisk IRC channel on Freenode, and after when I had a greater understanding of how things worked myself, I noticed a lot of people coming in asking the same questions I had based upon a misunderstanding of some terminology.
So, my goal here is to write a good Asterisk primer for the absolute beginner and explain some things along the way that tripped me up.
The primer is still under construction, so keep watching this space.