When BlackBerry architect Gary Klassen first came up with the idea for what became BlackBerry Messenger, his colleagues at what was then Research In Motion didn't understand why anyone would need anything except mobile email. Even his wife wasn't impressed.
"The first time I brought BBM home, I put two devices down on the table and I said to my wife 'watch!'. I typed in a message on one phone and it showed up on the other and she just looked at me and said 'couldn't you do that before?' I said 'no, no, it's different this time!' She wasn't convinced - but now my whole family uses BBM."
There has been one recent defector, Klassen joked. "My nephew bought an iPhone and he was ostracised from his community." But he'll be able to come back into the fold in the summer when BBM comes to iOS and Android phones.
Mobile is different
Klassen has been behind plenty of BlackBerry successes. He's worked on a wide range of BlackBerry products, from the 'old-skool' software all the way to BlackBerry 10.
He helped build the first ever colour BlackBerry phone before working on IM integration with services such as Yahoo Messenger, then moving on to work on HTML email. He even created the first version of the famous BlackBerry 'splat' to tell you when you had new messages.
In 2005 he came up with the idea of creating a mobile-only instant messaging system - an idea that didn't make sense to everyone.
"BBM was a bit of an underdog when it started. Not everybody believed in it; how could we compete against the incumbents such as MSN and ICQ? When we were working with Yahoo we could only do what the other clients did, but with this we would control both ends of the connection, so we could do a lot more.
"We experimented with all kinds of stuff that we thought were good ideas and found out they weren't. In a mobile environment certainty and reliability have so much more importance, and a sense of presence is different on mobile."
Showing whether someone was available to read and reply to your messages turned out to be a whole new challenge, and one that initially presented a few hurdles:
"There was a study in a college where they gave the students mobile IM and at the end of the study they were surprised to find that the students were really distressed by it, they didn't want to have anything to do with it." Klassen says, "Appearing online and available, when I'm not, causes stress."
The BBM team solved that by marking when a message had been delivered to the other person, so you knew the system was reliable, and marking when a message was read so you know whether you could expect to get a reply.
"When we added those Ds and Rs, we changed the paradigm," Klassen told us. "If I know the end point is another mobile, I get the implications. It becomes socially acceptable if I don't reply because I'm busy or I'm on a bus. And it doesn't rely on me changing a setting or the network being able to decide whether I'm available."
Generally, BBM users do reply pretty quickly. VP of software product management and ecosystem Andrew Bocking told us that BBM users spend about 90 minutes a day in BBM "and around half of the users read messages that are sent to them within 20 seconds."
Klassen and the BBM team knew they had a hit on their hands when the service started spreading virally inside the company. Despite the doubters who pointed out that they already had instant email, when Klassen showed off BBM, people started using it - even though he thought it wasn't ready.