One of the very good suggestions for thinking of a post is to answer an email. I would like to interject a small word of caution here - make sure it's ok to post.
Remember that if you have comments, they're bypassing them. While you may assume it's a hope that you'll ACTUALLY PAY ATTENTION, there may be other reasons - a sense of privacy or embarrassment being the easiest but not necessarily the only reasons.
A little tale. Many, many years ago I was working at a job. And I received an email that resolved some significant issues then ongoing, but raised others -- some of which were personnel related. Of note, however - the email's author was was not a fellow employee.
I copied large swaths of the post, and forwarded within my organization (with comment).
Some people within the organization were angered. And they came back with a completely unexpected attack - they got hold of the original sender's email (legal - if you don't think so you've not read about business email privacy issues) and contacted the original sender. THAT person registered a complaint against me for using his words without permission. Note, not "copyright" issues, but another deal entirely. It was ugly, and I wound up winning but got some scars in the process. One of the nastiest scars applies here:
I lost the trust of the sender because I didn't ask if I could use chunks of the email.
Ask. This solves copyright too - ask, get permission, and there is no more issue. Before you blithely kick out the question as the basis of your post, remember to ask the person.
By the way, I do still forget. I know - from experience, again - that if the email is in direct reaction to a blog post - that I can sorta kinda get away with posting without asking on legal/technical terms. But it could still leave bad feelings. I've been lucky. I recommend doing as I do MOST of the time and ask, not 'hoping this won't matter'.
It's a game. Have fun.