While working at some really old code that provided a fulltext search feature, I was at one point incredibly pissed rather unsatisfied due to the fact that said code resisted all attempts to debug it. This lead to the decision to sit down on a rainy weekend to try if I couldn't come up with something more useful, and most importantly, scalable.

His method allowed for separation between the indexing and the main app and how he changes some of his methods when he learned that Solr did something very similar. He also lays out some example XML content and how it's handled in his script (via a SimpleXML object).