A “Hello World” Server in Prolog
I like how posts about Prolog get populular very fast, but have little to no comments. People have heard that this language is special but have never actually used it in production, so they hope that someone will shed the light on it. Unfortunatelly it usually ends with a copypasted list of 15 projects(including Watson) where Prolog is used and thats it. 
Maybe someone can share his/her production level experience with it this time...