On a picture board I administer such a topic description is at max 255 characters long and used in this way:
- Subject: Milla Jovovich (51 x)
- Description:"Resident Evil: The Final Chapter" premiere, Roppongi Hills (六本木ヒルズ), Minato (港区), Tokyo (東京都), 13, JP, 2016-12-13
- Text: (the pictures only)
And this is used throughout the whole board. Non-picture topics also profit from this feature by writing summaries, which neither subject nor post text could be used for. The advantages are:
- board search fully supports it (searching 3 words means i.e. 1 can be in subject, 1 in description and 1 in post text - not sure if an extension can achieve this)
- descriptions are displayed in every topic list (viewing a forum, viewing search results, managing subscriptions, managing bookmarks...
The 3.0 MOD was only basically providing this while not providing any search support (which I consider the most important one).