Meta Tags

I am actually going to try some white hat SEO and I had just one question.

I read somewhere that you should write meta tags like this...

keyword 1 keyword 2 keyword 3 keyword 4 keyword 5 keyword 6

instead of with commas...

keyword 1, keyword 2, keyword 3, keyword 4, keyword 5, keyword 6

What do you guys think? It makes a little bit of sense to me because then you will rank for keyword combinations rather than just the keywords themselves.

If you are targeting G - don't bother using meta keywords.

Keep them short in count (so the don't look spammy). Using commas is just fine

I have read arguments of people saying they don't do anything at all nowadays and you shouldn't bother but why not use them? Not going to cause any harm is it?

I would usually use them with commas though