> people barely used them for talking to their friends

In the UK Blackberry and BBM remained very popular for a long time.

That Blackberry was additively used for email (even in a business setting) implies a lot of use for friends. The crackberry addicts were emailing their friends, who were likely also work colleagues, fellow execs, etc.

There's a viral quality to emails from BlackBerry devices as well. Didn't they add "Sent from my BlackBerry" to the end of emails by default? And then Apple famously added "Sent from my iPhone" by default to emails from iPhones.

Yes, that "Sent from my Blackberry" was the default, AFAIK. A very obvious signal that you're a smart important person with a Blackberry.

That's when the "Please excuse the typos, sent from my mobile device" became popular too.

I Canada at least and I think in usa too there was a period where blackberries were way cooler among teenagers than iPhone are today. In age where each sms used to cost money, blackberry messenger was uber cool.