The METATAGS_DIVIDER is used to separate dynamically-inserted category names. It has nothing to do with any custom keywords that you enter ... you can use commas or spaces in your custom keywords and the METATAGS_DIVIDER will be ignored ... because it's only used for dynamic building. Okay, now I'm repeating myself. But, I will repeat earlier posted content, hopefully in a little more clear manner for you:
So, if it's not doing that for you, then you've not edited the correct language file for meta_tags.php.
So, to recap what's been posted earlier ... typically that file would be /includes/languages/english/YOUR_TEMPLATE_NAME_HERE/meta_tags.php
(See the overrides documentation in the FAQs area for the explanation of what YOUR_TEMPLATE_NAME_HERE means in that sentence above)
Specifically, if *you* want to use a comma so that you're entirely comfortable that words are treated separately by the search engines, then you would change this:
Code:
// Define divider ... usually just a space or a comma plus a space
define('METATAGS_DIVIDER', ' ');
to this:
Code:
// Define divider ... usually just a space or a comma plus a space
define('METATAGS_DIVIDER', ', ');
(Yes, that's correct ... simply insert the comma, as shown).
Then the main metatags generator will read each of your category names, insert a comma and a space between each one, and then tack them on to the rest of the dynamically-generated meta tags along with your custom meta tags.
If all of that is not working for you, then the only reason would be that you have altered core code that handles the metatag generation ... namely /includes/modules/meta_tags.php ... BUT THAT FILE SHOULD NOT BE TOUCHED under normal circumstances. Nevertheless, feel free to play at your own risk.