It's not that it's hard to code, it's that a aimplistic approach will lead to questions that might not be intuitive. If you use Euclidean distance, then you es

It's not that it's hard to code, it's that a aimplistic approach will lead to questions that might not be intuitive. If you use Euclidean distance, then you essentially count 1 for each word difference. That means long posts will have longer distances from shorter posts with the same topic. If you fix that by treating "important" words differently, then you have to figure out importance, and then normalize by number of terms, etc. Before you know it you're building a naive Bayes classifier. Again, the challenge isn't in the coding, it's in understanding the limitations of the more simplistic design.