The press release has a number of interesting stats, with the availability of Bango's operator billing driving the sale of digital goods (in-app purchasing, registrations, etc) up by 300-400% in developed markets, and upwards of 1000% in markets where there is little credit card penetration.
Microsoft are quoted as saying that operator billing is preferred by 75% of users who have it as an option, and it has a positive net effect on sales.
Operator Billing is one of those ideas that has been around for a long time, and has had a number of implementations on various platforms (notably Nokia's Ovi Store on Symbian OS), but it is still patchily implemented. Where it is implemented, it works well and there is far less friction in the purchasing process.
You can find out more at Bango's website, and we're expecting to hear more from them during 2013.