Erin Kissane, after giving birth to her daughter, spent a lot of time away from “the big-screen Internet,” limited only to the occasional smartphone tap or swipe:

Combine that with a slightly bumpy recovery from surgery and all the sleep deprivation you can expect from life with a newborn, and I’ve had plenty of very recent experience using the web while bleary, impatient, and on a device smaller than my hand.

All her lessons about mobile usability are great, but this one is the truest of the true:

Slow load times make me hate you. If I’ve been staring at my phone for 30 seconds while your site loads bushels of unnecessary files, not only am I going to back out of the site, I’m going to mentally put it on my Google results blacklist. Likewise, if you override my ability to pinch-zoom, use a mobilizer that makes me swipe instead of scrolling, or adds pagination, I will go out of my way to never use your site again.

As Erin puts it: “Mobile-only internet use is only expanding, and this group of users is much too large to ignore. And don’t forget — if you’re sufficiently unkind to a multi-device user stuck on a small screen, you may find they avoid you on the desktop as well.”