54 of the world's top 100 companies use Instagram

"With over 100 million users, more brands are recognizing the powerful reach and potential of Instagram. 54% of the world’s top brands using the mobile network to engage consumers. In our quarterly study, we take a look at who’s doing it, how they’re doing it, and who’s doing it the best.
When we first studied Instagram adoption in August, brands were starting to engage on the network. Three months later, the brands who adopted early are seeing month-over-month growth, creating a bigger gap between themselves and brands who haven’t started using the service."

Source:  Research by Simply Measured, 31st October 2012