Receptional_Andy - 1:53 pm on Sep 3, 2008 (gmt 0)

I've seen some pretty spectacular meta keyword elements over the years (5k meta keywords anyone?) but ever never seen any real impact on Google results in changing them, cleaning them omitting them, whatever.

IMO the complete lack of standardisation in terms of what should be included in meta keywords tags means that webmasters with clean sites include 'spammy' keyword elements in all innocence - believing that, for instance, all of the output from a keyword suggestion tool would be helpful, or the entire textual content of the page separated by commas. For that reason, I think it is a wise decision for a search engine to ignore or place little weight on the content of meta keywords.