A long blog post (850 to 950 words) is an excellent opportunity to provide unique value to your readers/potential customers. Separate yourself from other businesses by showcasing your expert knowledge. For example, you could use a long blog post as a how-to, explaining in detail how someone could redo their kitchen or beef up security at their business.
There's a lot you can do with this format, from running a question-and-answer column to posting excerpts of a white paper or e-book. As long as the navigation is intuitive, with headers, bullet points, and images throughout, this type of blog post can be accessible to all readers, whether they are checking in from a computer or mobile device.
Longer blog posts tend to do better for search ranking purposes because they can answer multiple questions thoroughly, so having a long blog post among a group of short and standard blog posts lets you combine the best of two worlds: ranking highly and delivering varied types of content to readers.