This page no longer works as intended, it seems. You’re linked to it from here on the website.
Edit: Also, the donation link here doesn’t seem to function as it’s supposed to either.
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.