My friend Doc Rogers points me in the direction of a piece of research by Donald Gunn, he of the Gunn Report, who has determined that all ads fall into one of 12 categories - or "master formats," in his words.

This slide show presents some recent ads exemplifying each of Gunn's 12 basic categories.

Does Gunn have a point? Or are his categories meaningless? Well, even he admits they are pretty arbitrary, in as much as several of them blend into each other.

And if he does have a point, could his system be useful in any way? It feels more like a system for classifying ads after they've been written, rather than a technique that could help in coming up with them.

The very idea that there could be a "system" for creating adverts is laughable wishful thinking, isn't it?

And yet... maybe as a series of starters they could be useful, for when you're stuck for inspiration.

John Webster apparently used to pop down to WHSmiths and flick through the greetings card section, when he wanted to get his brain working. Nowadays, I suppose there's YouTube.

So I may just take one or two things from Gunn's list.

We all need 'starters' sometimes.