Could be a nice feature for display on channel website.
Also, caches links!
The link database uses a hash of the URL (cleaned from potential tracking params) to store the data. If there's already a document, use it if it's fresh enough, otherwise, re-try crawling and update the document.
Then a second database does the relations message/channel/link/rev.
The channel website could list the recent links posted on the channel.
Subsequent commands could be run on the link as well, such as requesting a web.archive.org / archive.today, ….