LOLCats may’ve been LOL back in 2005, but the internet is a fickle mistress and new memes soon become discarded and oh-so-last week quicker than you can say “Impact Font”.

But why? And just how long is the LOL-cycle of a new meme? Mike Rugnetta from PBS’ Idea Channel takes a fascinating look at why and when memes stop being funny and start being really annoying.