[timskii]

Extra keywords are based on tags. If there are no tags on the page, there are not extra keywords.

All this does is take meta information that is already available within the data structure of the forum, and put it into an HTML meta field.

One could gather additional meta information by distilling the content of pages. But I suspect Google/etc would be better at distilling the content of the page automatically than any plugin. So I don’t anticipate making this much more complicated, although there are no doubt a few easy enhancements that can be made.