[Plugin: Yet Another Featured Posts Plugin (YAFPP)] [Plugin: Yet Another Related Posts Plugin] Weird

Hi,

I don’t get how this plugin works. I have two posts with exactly the same tags yet the plugin doesn’t see them as related.

Except a small minority, almost all my posts have zero related posts according to the plugin.

So I wish to know how does this plugin basically works ?

http://ww.wp.xz.cn/extend/plugins/yet-another-featured-posts-plugin/