Aaron Wall writes a good post titled Rambling too Much = Bad Blogging.
I agree that rambling isn’t good blogging practice, but I wouldn’t say that all long posts are. To me it comes down to weighing up the individual factors that a blogger and their blog face and finding your own ideal post length.
Aaron sums his post up with this good (and concise) statement:
“If you are going to be longwinded make sure it is so focused, topically relevant and interesting that it becomes the industry standard for that topic. Elsewise you are best off writing quick posts.”