Excerpt from this article:
Reading them does make you feel closer to her, in a way: It sounds as if she’s speaking quietly, or sending you a handwritten note.
Sometimes I tweet in lowercase in an attempt to sound funny. A friend of mine emails exclusively in lowercase, and getting them feels like hearing her actual voice. A woman I know recently apologized to me for sending an email all in lowercase, which was touching and seemed unnecessary, but since we didn’t know each other well, it also felt like a complicated compliment (that she’d have been comfortable enough to email me in lowercase in the first place, but uncomfortable enough about it to think it was worthy of an apology).
Is it cool to type in lowercase? Is it lame? Does it all depend? While typing in lowercase seems simple — it’s casual, it’s easy — it signals an array of sophisticated/nuanced approaches. You can wear lowercase like a costume. It can be evil, it can be gentle. It can be light, it can be dark. And so, here’s a sort-of-comprehensive list of all the reasons we type in lowercase, specifically in email and DMs.