There have been recent posts that reflect in-depth knowledge and significant effort to provide comprehensive information on a topic (examples here and here).

Yes, it's possible to bookmark these posts for individual reference. However, Tildes doesn't have a pinning feature given the current very loose organization of subjects/interest communities.

In that absence, I'd like to suggest a globally used ".wiki" sub-tag appended to topics, to narrow search results to highly informative entries on a subject.

Please let me know your thoughts on this.

I'd go ahead and add the .wiki sub-tag to a couple of entries myself, but I've lost tagging privileges after a long stretch of inactivity. Please consider that I'm interested in volunteering again.