Questions and answers normally remain on AB forever, in order to provide a resource for people in the future.
However, when some people have had particular reasons for wanting to have their posts removed, the Editor has sometimes granted their request. (Use the 'Contact Us' link at the foot of this column).
In an extreme circumstance one member has emailed me, asking for me to ban her so that here presence here would completely disappear. I complied with that request but, as I've stated, that's a particularly extreme way of getting posts removed!
Chris