What tried and true algorithms for suggesting related articles are out there?

Question

Pretty common situation, I\'d wager. You have a blog or news site and you have plenty of articles or blags or whatever you call them, and you want to, at the bottom of each,

Answer 1

This is a typical case of Document Classification which is studied in every class of Machine Learning. If you like statistics, mathematics and computer science, I recommend that you have a look at the unsupervised methods like kmeans++, Bayesian methods and LDA. In particular, Bayesian methods are pretty good at what are you looking for, their only problem is being slow (but unless you run a very large site, that shouldn't bother you much).

On a more practical and less theoretical approach, I recommend that you have a look a this and this other great code examples.