How does Stackoverflow's homepage filtering work?
I believe the questions that appear on the homepage are specifically related to your interests, which are indicated by the tags that you look at, question ans answer.
Does anyone know the name of the algorithm/technique or have some basic details (nothing that violated their IP) about how Stackoverflow goes about only showing what is relevant to each person.
Is it a Bayesian filter, similar to spam filters? Or something else?
Actually, it looks like the filtering isn't related to that at all. It's just the most recent activity taking into question ageing.
It's nothing near as sophisticated as you seem to think it is. The main front page just shows the top N "active" questions, without regard to your "interesting" and "ignored" tags.
The tags only affect the styles applied to certain questions. Questions with interesting tags get highlighted, and questions with ignored tags get grayed. The tag-specific styles are applied on the client end; sometimes, you can see the styles applied after the page has already been rendered once on your browser.
I think they base on the question's tagging and clasification. But I think if they were using some specific user information they would base on your profile activity and interests to show you what you're most interested to see.