So in general: Should I report posts of casual discussion on a loosely related topic which span over about a page?
If the discussion has some relation to the topic specified by the topic post, then it's usually OK. Here's an excerpt from the moderator guidelines:
Off-topic posts
Almost everyone gets posts split/deleted due to off-topicness. It is the most common error. I've made the error myself several times.
Every reply to a topic should be a response to the OP. When someone reads the OP, they should be able to guess more or less what the replies will look like.
It is quite natural for replies to actually only respond to some point of another respondent. For example, you might want to point out a small and trivial error that another poster has made. However, this kind of replying is usually off-topic.
A reply to another reply is on-topic when it contributes to the on-topic discussion. For example, it could build onto or refute the on-topic arguments of an earlier reply.
Posts may contain off-topic remarks in addition to the on-topic arguments. The off-topic remarks can be more substantial than the on-topic remarks, though as a very rough guideline I'd say that for every three paragraphs of off-topic arguments there should be at least one of on-topic arguments. Text that replies to this off-topic text is also off-topic text.
Posts consisting of ad hominem attacks or other useless text are always off-topic.
Sometimes some leeway is given when the topic starter seems to like the off-topic replies.
Bump-only replies are OK if they don't become annoying. Delete these useless replies once more replies have been posted and the bump is no longer necessary.
The phrasing of the topic post gives hints as to how strictly to enforce on-topicness:
- Topics with vague topic posts may cause "chaotic" replies to actually be considered on-topic. Topics that contain no questions are especially prone to this.
- Non-answer replies to a topic consisting of a specific question are likely to be off-topic.
- General topics about a service created by the service creator can contain criticism of the service unless otherwise specified in the OP
- Announcements can generally contain any comments about the service that was announced
Topics in the "off-topic" section still have the same on-topicness rules.
When in doubt, wait until a couple of people have reported the potentially off-topic posts.
The policy about off-topic posts is non-optimal, but I think it's the best we can do with flat (non-threaded) discussions.
Should I report each of them or is reporting the first or the last one sufficient? Also should I report the post from which the discussion deviated from?
Reporting all of them is often helpful. If you're going to report just one post, report the first one which should be deleted.
