Isn't this widely known and very old trick? I'm pretty sure I even saw youtube tutorials and non-techy people discussing there is a way to find a person's twitt

Isn't this widely known and very old trick? I'm pretty sure I even saw youtube tutorials and non-techy people discussing there is a way to find a person's twitter account by their number. This article says like it's something recent that was only available for short time and quickly fixed. Doesn't seem like that at all.