I've found actually that most people don't seem to get upset if the thread goes off topic. But a few do. I know who some of those are and try to respect. Sometimes someone will mention it in their thread and try to bring the thread back to their original concern, so I desist if I'm part of the off topic discussion. But I think, as has been shown by the number of people responding in the affirmative here (good Spock talk), that quite a few are fine with their threads straying.