There are many old questions showing on the start page of superuser.com. If I open one of them, I see old dates both in answers, comments, and the editing time of the question.
How/why are these get to the top?
What can cause a question to be "bumped" to the first page in the Active tab of a Stack Exchange site? (Changing the "Last Active" date.)
The following activities will cause a question to be bumped:
- Addition of an answer
- Editing the question or any of its answers (even if the answer is deleted) * † ‡
- A suggested edit gets approved
- Editing duplicates list of the question
- Starting a new bounty (not awarding of an existing bounty, see below)
- Successful reopening (if the question was closed previously)
- The Community user will bump non-negatively scored, open questions every hour that have at least one answer scoring 0 and none scoring more than that.
- Questions are picked randomly from the top-viewed questions with new activity more than 30 days ago.
- The maximum number of unanswered questions bumped per hour depends on the site: 4 per hour on Stack Overflow, 2 per hour on Super User and Server Fault, and 1 per hour on Meta Stack Exchange and all other sites.