I've observed that old questions with answers that were confirmed to solve the questioner's problem as indicated in the comments or self-answered, yet not marked as accepted. After a sufficient amount of inactivity these questions bubble up over and over again with "modified x hours ago: Community".
Here's a few examples:
Place images in page center in epresent-mode
How can I delete all the gdb related windows/buffers after `q` in gdb CLI window
Emacs connect to MySQL (MariaDB) non-interactively
Is there anything specific we can do about those to get them marked as accepted?