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What is BlackBerry Messenger and how does it work?

There are lots of quick messaging tools for the various smartphones on the market, from text messages, to cross-platform group MMS tools like WhatsAp to Facebook chat integration on Windows Phone to mobile versions of the classic IM services, but only BlackBerry has BBM; BlackBerry Messenger and What is Blackberry Messenger? And assuming RIM isn’t having one of its incidences of Blackberry Messenger not working, BBM is faster and more reliable than other messaging services – and it’s free. How does RIM manage it?

Device to device

If you want to send a New Year’s greeting at the stroke of midnight, your text message might take hours to get delivered or not get sent at all; the mobile networks are notoriously overloaded at peak times like New Year’s Eve and World Cup finals. As long as you can get a data connection with your BlackBerry – and that includes connecting on the free Wi-Fi at your hotel abroad even if you’re not paying for roaming data – your BBM message should be delivered instantly. And you can tell; you get to see in BBM when the message has been delivered, and when it’s been read. And whether the BlackBerry you’re sending a message to is in London, Paris or Australia, there’s no cost for the message itself (just a tiny piece of your data plan’s allowance used up if you’re using your mobile data rather than Wi-Fi).

You have to have a BlackBerry data plan to start with (or the Feature Enabler add-on that some mobile operators offer to give you limited BlackBerry features like email and BBM without paying for a full BlackBerry data plan), because that gives you an account on the RIM servers that receive and send the messages. When your BlackBerry is provisioned with a data plan and you have the right service books on the device, even with the phone radio off you can connect to the RIM servers over Wi-Fi; if you’re connected correctly, the Wi-Fi icon at the top of the screen will be white rather than grey, and BBM messages will work.
BBM is efficient. If you’re using an instant messenger client on your BlackBerry, it has to stay connected to know when there’s a message for you; the push notification service makes that reasonably efficient but it’s still going to use a little extra battery power. Because BBM messages come over the same connection from the same servers as your email, staying online doesn’t mean turning the radio on specially or using up more battery life.

BBM was originally known as PIN messaging, and you had to know the PIN of the BlackBerry belonging to the person you wanted to contact; if you were in the same place, they could get their BlackBerry to show a 2D barcode on screen that your BlackBerry could recognise as their address. Now that you can set up a BlackBerry ID to use BlackBerry services like App World, you can also add contacts to BBM using that BlackBerry email address (they still have to accept your invitation to connect before you can send them messages).

You can send the same BBM message to several people and see all their replies in the same conversation (and everyone sees all the messages). Unlike SMS, BBM messages don’t have to be just text; you can send a picture or a voice recording, your location or contact details. Or you can send a message that’s actually you taking a turn in a game if the app uses BBM; there are around 200 apps that use BBM either to send messages to other users of the app or to share information. If you’re watching a football match, you can use the Sky app to send messages about a goal to friends who are watching the same app.

You can see where local BBM friends are with the Wikitude augmented reality app. You can share your favourite music with BBM friends using the new BlackBerry Music service. Or you can just play a game of Battleships with BBM friends. All the messages go through BBM, so they’re delivered straight away if someone is looking at their Blackberry.


You can only send BBM messages to other BlackBerry users; you can add other contacts to the BBM address book by putting in their mobile phone number, but when you send a message to them from BBM, it’s just a normal text message (that you get charged for) and you don’t see when it’s been received or read.

Millions of messages

BBM is popular; there are 50 million BBM users (up from 28 million people this time last year, with around 2 million new users signing up a month). That’s pretty good compared to other online services like the 75 million users of the PlayStation Network, and RIM says three quarters of those users are sending messages daily, with over 100 million messages sent every month (although that’s nowhere near the 11 million text messages UK phone users were sending every hour in 2010 – the last year the Mobile Data Association has figures for). For special events that goes up; there was a 300% spike in BBM traffic after the final goal of the 2010 World Cup.

That’s a lot of people for the RIM servers to handle, which is why RIM had so many problems when a fault in a router in the UK data centre meant the servers got overloaded during the summer. Every message is sent from your handset over the same SSL-encrypted connection used for email, stored on the RIM servers (still encrypted) and then forwarded on to the BlackBerry of the person you’re sending it to; once it arrives, their BlackBerry sends an acknowledgement to the server which marks the message as delivered on your BlackBerry. When they read it, their BlackBerry sends another acknowledgement to the BlackBerry servers, which update the status of the message on your BlackBerry to ‘read’.

RIM doesn’t share many details about the BBM infrastructure; we do know that all the servers are set to fail over to backup servers on another continent if there’s a problem (the connection to the backup servers seems to be part of what failed during the outage). The ever increasing build-up of new messages arriving on the servers meant that the longer the servers were down, the more traffic other systems were trying to deal with, because until each message has been delivered, it isn’t deleted from the servers.

Because they’re encrypted, RIM can’t read your messages while they’re on the BlackBerry servers. When police suspected that some of the looting during the riots was planned in advance using BBM, what they asked RIM for wasn’t the contents of the messages. It was information about the messages called traffic data – the pattern of messages passing between certain users. Seeing a pattern of frequent messages between specific people just before each incident is going to make the police suspect those people are involved in those incidents without needing to see what they were talking about (of course, these could be perfectly innocent messages sent at those particular times by pure coincidence).

One of the things RIM is planning is to use BBM for buying things. Take a BlackBerry with NFC that you can tap on a credit card reader and a BBM message that arrives straight away as your receipt and your BlackBerry looks a lot like a mobile wallet, especially when you can pay for a cup of coffee on your mobile phone bill the same way you can buy an app. That means users will have to trust BBM, so we’re expecting to hear what RIM has done to make the BBM infrastructure more robust – but at the moment, BlackBerry is the only platform offering fast, free messages that generate receipts, because it’s the only smartphone that has to connect to a server to work.


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