See here for a description of how Google’s PageRank algorithm works. You’ll need a little bit of matrix theory to completely be able to follow the description, but it’s nothing too horrible.
Hmph. For some of us, the two halves of this sentence do not go together. 
I saw all three Matrix movies. I should be good to go.
::SNERK::
I was doing well with the article until I got to “We will assign to each web page P a measure of its importance I§…” and then my brain completely stopped being able to comprehend anything further (although the shaded blue graphic was helpful).
That is pretty much how my high school math career went, too. Kickin’ ass and takin’ names until algebra 2. Then they started telling me numbers were letters and vice versa - not to mention adding in all sorts of non-english letters - and my brain exploded.
I like Algebra 2 so much I took it twice!
I came third in my high-school math contest.
I did not understand the mathematical details of the linked page.
The geeneral explanation was quite interesting, though, especially the idea of sections of the web with no outbound links ‘draining the importance’ from other areas…