Should you read an entire thread before responding?

[Phil]

There seems no point in posting unless you have read all the previous posts. I sometimes wonder if some people are just trying to boost their rankings but it is frustrating to read a post that seems completely irrelevant because someone just wants to go off on their own particular tangent.

[Standard]

I usually try to read all the postings before responding to a thread. However I do admit to having responded to a thread after only the first or second page of a multiple page thread only to find out that someone has posted a similar comment further along the thread. It is nice to see the differing views of our members, and the way that a thread progresses and evolves, sometimes taking a turn well away from the original post.