In the post Rands Response Hierarchy, the author outlines his response window and probability of reply to various methods of communication:

There are a great many ways to get in touch with me. With the establishment of Slack as a primary means of communication, I realized that I had updated the prioritized hierarchy to how likely I will respond to a piece of communication. From least likely to most likely, this is the hierarchy:

For a long time my Contact Peter Rukavina page has included the hint “I prefer email.” Sometimes people read that. Sometimes people read that, call me on the phone, and apologize for not following it (which is okay; it doesn’t say “don’t call me”).

Here’s my own “response hierarchy”:

Spam < Twitter < Email < Slack < Phone < SMS < Face to Face < The Post

• Spam: I never respond. Like Rands, I ignore spam. Some of it still slips through, but it’s mostly of the easily-identifiable “I can write a highly targeted post for your blog,” “We couldn’t deliver your UPS package,” or “Outstanding Invoice!” type that I can blow through.
• Twitter: I respond slowly. I still have a Twitter account, even though I’ve stepped away from it practically. So I’ll see your direct message, but it might not be for a while.
• Email: I usually respond the same day. I’m not one of those people with an unmanageable inbox, and I do a decent job of “inbox zero” at the end of every day. So I usually respond quite quickly, unless I’m flummoxed.
• Slack: I respond right away, if I work with you. I don’t use Slack as a broad interest-based chatting tool as others do: I chat with my coworkers only. And if I’m in the office, or I hear my phone go off, I’ll respond immediately.
• Phone: I almost always answer. The only exception is “Unknown Caller” or mysterious toll-free numbers, which I will ignore, especially if I’m busy. I don’t screen my calls otherwise, so if you call me and I don’t answer it’s most likely because I’m away from my phone or I’m asleep.
• SMS: I respond right away. Generally I get texts from family, from Oliver’s school, or from colleagues. I include Signal and Google Hangouts in this category, although I’ve only got a limited list of people I’m connected to that way.
• Face to Face: My contact page should really say “I prefer face to face,” as I really do. I have more fruitful conversations on street corners and in the coffee line than anywhere else. If I don’t stop to talk to you it’s only because I’m in a hurry to get somewhere.
• Letter in the Post: If you mail me a letter, there is a near-100% chance that I will respond, as long as you’re a human being and you’ve mailed the letter only to me. I throw away all junk mail, though, especially from charities that I’ve donated to that want me to donate again.

Missing from that list are Facebook (I resigned), LinkedIn (it has chat? I’ve never used it), legacy IM services (AIM, MSN Messenger, Yahoo! Messenger) which I’ve stopped monitoring.

So, there: go mail me a letter right now!