Is there a different in exposing details from your life on a blog or doing so in a memoir?

Well, one difference is that unless you are famous, a fabulous writer, or have led an incredibly interesting life (other than in your own mind), you won’t be publishing a memoir (self publishing doesn’t count).

If you did do a memoir, the publisher spends a lot of money promoting it. That is something that does not happen with most blogs. So, again, unless your blog is extraordinary or you are an awesome SEO wizard, it will not be read by as many people as a memoir.

One other difference I believe is the case based on what I know of both processes, although it is really speculative on my part, is that people writing a memoir spend much more time and thought on what they include and how they say it than bloggers do.

Blogging is about the now. It is usually short and replaced by new content rapidly unlike a memoir, which is crafted over time after reflection and goes through several more different reviews and edits and time for reconsideration than blog entries.