Algorithms for finding similar questions based on another question's title?

Question

For example, every time I post I question on stackoverflow.com, the UI suggest me plenty of similar questions. How is it functionality implemented? Are there some well-written algorithms about this?

Answer 1

They use the full text search feature in MSSQLServer

http://highscalability.com/stack-overflow-architecture

SQL Server's full text search is used extensively for the site search and detecting if a question has already been asked. Lucene.net is considered an attractive alternative.

I think they talk about in it one of the podcasts too?

Answer 2

I actually have the whole source code for StackOverflow right here. It's pretty easy to understand:

class StackOverflow
{
    static void Main(string[] args)
    {
        JonSkeet();
    }
}