Facebook is still the most widely-used social network among mobile users but downloads of its iPhone app are stalling as similarly-themed apps such as Instagram, Skype and Twitter achieve growing popularity according to research.

Analytics firm Distimo has released data indicating that although Facebook was the most popular social network among mobile users in the two years to June 2012, the growing popularity of rival apps, such as Skype and Twitter, appears to have dented its download figures more recently, see graphs below.

Source: Distimo

Source: Distimo

Among ten of the largest markets in July 2012, Facebook clearly was not the largest social network application in terms of downloads, according to Distimo analyst Gert Jan Spriensma, although he pointed out that downloads do not equal active users.

“As the Facebook app has been around for over three years now, the adoption is already high,” he said adding that Instagram gathered much more downloads in July 2012, and that Whatsapp was the most dominant paid-for app in the sector across Western Europe, see below.

Source: Distimo

“Instagram could have potentially harmed Facebook’s dominant position, which might indicate why Facebook acquired it [for a fee of $1bn],” read Spriensma’s analysis of the findings.

“Aggregated over these ten countries the clear winner in terms of downloads in July 2012 was Instagram, followed by Twitter and Facebook.”

Distimo’s report, which was compiled using transactional data via its analytics tool, and correlates with separate information from Experian, which also indicates that more “niche networks” are on the rise in the last year.

The data firm recently released data indicating that niche networks such as Instagram, Tumblr, LinkedIn and Pinterest rose steeply in popularity across the globe, see chart below, with some achieving quadruple-figure growth in the UK in the 12 months to July.

Source: Experian

A more in-depth analysis of the statistics revealed that Instagrtam and Pinterest achieved the highest levels of year-on-year growth in terms of UK users although others remain popular, see below, with Tumblr and Reddit also registering good momentum.

Source: Experian

James Murray, Experian ‘s digital insights manager, said, “The growth of both Instagram and Pinterest over the past year has been phenomenal. The reason for their success is that they haven’t tried to be ‘another Facebook’. Instead, they both identified a gap in the market and used the scale of Facebook to reach consumers.”

“Over the next 12 months, we expect to see a proliferation of niche social networks.  Offering deeper functionality combined with a lower technical barrier to entry will mean new leaders in social media being created in a matter of days versus weeks and months.”