For what's pretty much the oldest form of online communication, you'd think we'd have gotten the hang of it by now. There's some excellent advice here.
Nothing drives people crazier than an email where someone sends over a lot of information but doesn’t say what they’d like you to do. I often respond to those immediately by asking: What do you want me to do?
Do you want me introduce you to someone? Do you want me read your blog post and give you feedback? Do you want me to respond with whether I’ll be able to attend an event? Be clear and say it explicitly up front.