Duplicate Metatags Option


I love XF but what I miss is the option to add metatags to pages (for example the forums main page) and postings (the first post of a thread). My users should have the option to add tags next below to the wysiwyg editor and these tags should appear below the thread and act also as meta tags.

In case, users do not add tags, XF should have the option to pick the most used keywords out of a post and use them as metatags.