So what is a 'blug'?

I'm on a roll here (or should go to bed). So what is a 'blug'?

blug - an advert on a blog (i.e. a plug).

So what would those in adverting be called I wonder?

Not that I have anything against advertising, just a bit of fun.

I suppose I should say 'not that I will ever have anything to do with advertising' as I have such a sorry number of hits. The blogness persists ...