A reputation is the number of votes your writeup receives.

Initially, a post has a reputation of 0. If one or more monks finds it of (dis)interest, are at or above the "novice" level, and has votes remaining (see Voting/Experience System), s/he can vote accordingly.

Because your writeup has a reputation of 2, that probably means that a couple of monks found it worthy of one of their votes.

Another (unlikely) scenario is that of the monks that voted upon your writeup (x>=4), (x/2)+1 found it interesting.

Addendum
For what it's worth, someone apparently didn't like this writeup, and gave me a vote--. Is the above data incorrect?

Ah, democracy in action.