Greetings Sam, thanks for your comment.
With a blog, there is generally a greater expectation of more substantive content, and people are more prone to take time with it than with a tweet or Facebook post. Perhaps they have come from a tweet, or other smaller communication with the epectation of getting something more.
However many of the same principles apply - you need to catch people's interest early and draw them into your narrative. Also, do not have great expectations of a high percentage of people finishing, or meticulously digesting, your prose, no matter how well written and relevant it is.
You need to hit them with something they are wanting quickly, maintain a solid pace, and deliver the critical messages efficiently. I would say blog posts shouldn't be above 700 words without good reason.
Typically there will be some type of call to action for those who want more still.