When Facebook enabled phone number registration for its Messenger app on Android earlier this week, it selected five countries for the initial roll out but it never provided a reason as to why these countries were selected. The countries are Australia, India, Indonesia, South Africa and Venezuela. Aside from India, all the other countries are on the southern hemisphere, but what would prompt Facebook to choose them? Because it doesn’t look like the selection had anything to do with WhatsApp.

The selection can’t have been random and the geographical coincidence is just that, coincidence. In terms of the numbers of Facebook members in those countries, it doesn’t provide a reason behind the decision. India and Indonesia are third and fourth in Facebook membership numbers, while Australia and Venezuela are 21st and 22nd and South Africa is down at 32nd as you can see from the table below, from Facebook monitoring site Socialbakers.

This comment on The Verge by Itsukki on a post about the announcement of the service though, gave the much needed clue to investigate further why Facebook had chosen these specific countries. Knowing that BlackBerry is popular in India, it occurred to me that aside from iPhone-mad Australia, Facebook had chosen BlackBerry nations.

Indonesia’s love for BlackBerry is well documented in DailySocial but not so much the other countries. This Quora thread gives some idea as to the prevalence of BlackBerry in Venezuela. The question may have been asked and answered over a year and a half ago but it’s still a relatively recent period. This article on memeburn reveals some more about the use of BlackBerry in South Africa while Engadget has covered in detail over the last couple of years about the popularity as well as the drama surrounding BlackBerry and RIM in India.

The remaining unexplained country is Australia. Consumers there are known to be mad about the iPhone and it is one of the top iPhone countries in the world, so why the inclusion? This July story from Sydney Morning Herald may shed a little bit of light. As it turns out, as of this year, BlackBerry is still widely used across corporate Australia although in diminishing numbers and companies have been preparing for post-BlackBerry life.

The article mentioned that RIM is making a concerted effort to maintain visibility and favorability among Australian companies and it seems to be working to ensure that it’s holding on long enough to allow the introduction of BlackBerry 10 to Australia’s enterprise market. Remember the viral “Wake Up” campaign from early this year? That was RIM.

So, it looks pretty clear that Facebook had selected countries in which BlackBerry usage is still prevalent although to a lesser extent in Australia. The high adoption of RIM’s devices means there’s a pretty good chance that consumers in these countries, perhaps with the exception of Australia, are still beholden to BlackBerry Messenger and Facebook is targeting these people in addition to WhatsApp users.

One curious fact remains however, that in the UK, people were using BlackBerry Messenger to coordinate the riots that broke out last year across the nation, which means its use is also prevalent there. For some reason, Facebook did not include any part of the UK in its initial roll out. One wonders how much, if at all, the state of the economy and consumer buying power play a part in the decision.

And now the questions. Why target BlackBerry nations and not roll out the feature to Facebook’s BlackBerry app to begin with? Do these countries have a high Android adoption rate? Indonesians are quickly adopting Android and according to recent data, the green robot has surpassed BlackBerry in overall popularity in this country. Is the same thing happening in those other countries as well and how much does that factor in to the roll out?