Do you mean why do Bran Flakes get mentioned on this site so much?
The tune to an old advert for Bran Flakes ("They're tasty, tasty, very, very tasty - they're very tasty") crops up often on this site. Many regular users get annoyed at the frequence of questions asking what product "They're tasty tasty" referred to.
It's because we had a rash of Qs asking what ad "tasty, tasty etc" was from a few months ago. I think it must have been a competition. Hence Qs which crop up repeatedly and where the users don't seem to have checked whether it has been asked previously are sometimes referred to as 'bran flakes'.