YFast is a PHP class developed to use on this blog, it gives you the possibility to use all modern technics of web development (etags, gzip, exipire headers) on your site in a very simple way -- and get A on YSlow.-YFast is a PHP class developed to use on this blog, it gives you the possibility to use all modern technics of web development (etags, gzip, exipire headers) on your site in a very simple way-- and get A on YSlow.