依頼のメールは3行以内。

というのをPaul Grahamが言っていた。それ以上長いメールは読まないそうだ。
もしくは後回しにする。ということらしい。そして、一度後回しにされたメールに返事が来ることはないという。

確かに3行以内で書いたメールの返答率は高い。まめ知識。

http://paulgraham.com/info.html

あれ、いまみたら２行のメールにはすぐ返信するってかいてあるなあ。

Before emailing...
Is yours a Frequently Asked Question?

Unfortunately I now get so much mail that I can't promise to respond to every one. I know this seems obnoxious, but I notice I have mails in my inbox that are two years old. I'm probably never going to respond to them, and I may as well admit it.

I respond faster to emails that are short. Two-liners I often reply to immediately. Long emails I leave in my inbox to deal with later, and never do.