One well set diagram in a crucial post for a topic lifts readability enormous. Multiple diagrams in a post show mostly a lack of thinking before writing.

Count me as one who finds it annoying to encounter/have to scroll past posts with multiple diagrams.

Recently in our forum we've seen a number of posts that make rather liberal use of diagrams.  My personal view is that diagrams should be used sparingly, and should be reserved for situations where the position itself is the object of consideration.  This would tend to rule out their use merely to illustrate some point along the path of some line or other.  A rule of thumb is perhaps, if this is a position (1) that is critical and (2) where no particular move is being proposed, then a diagram may perhaps be called for, otherwise not. 

Here's a case where the use of the diagram falls within the proposed criterion: http://www.chesspub.com/cgi-bin/yabb2/YaBB.pl?num=1258628747/24#24

Though even there, it could be argued that the diagram wasn't really necessary.

I post this to see what others think about it.