Meta Keywords

[justinleeldn]

I know these are hardly used anymore, but please hear me out...

If i do decide to use them, do they have to be purely words, or can they be phrases?

Example:

<meta name="keywords" content="used, cars, sale, london, kawasaki, motorbikes"/>

Or

<meta name="keywords" content="used cars for sale, london, kawasaki motorbikes"/>

Thanks