For a company whose annual losses grew 40 percent to £36.8 million in 2008/09, this is going to be incremental revenue, rather than a magic bullet.

But it’s not to be sniffed at. Considering most counterpart newspapers’ apps are free and ad-supported, this is healthy income indeed - and, on the above rough calculation, already equal to half of one reporter’s starting salary.

What’s more - this may well be sustainable, if not improveable. Guardian.co.uk is popular at home in the UK, but also has a faithful U.S. following for its “liberal” news. Two days after launch, the app is currently #1 amongst iTunes’ top UK paid apps and paid news apps, and #2 amongst U.S. paid news apps.

Guardian digital content director Emily Bell can’t help but remark on the “irony” that the app for Sky News (operated by the particularly pro-paid News Corp.) is top of the equivalent free chart.

A comparison with free, ad-funded news apps would be interesting. For example, the day-one Guardian.co.uk app income may well be favourable to that from the Dell and Cisco (NSDQ: CSCO) sponsorships inside Telegraph.co.uk’s free app (though we don’t have Telegraph.co.uk figures to show).

Other Guardian income ideas include a readers’ club, launching in 2010, but the paper considers charging for the website - including on mobile - “a stupid idea”.

Disclosure: paidContent:UK’s parent company Guardian News & Media is a wholly owned subsidiary of Guardian News & Media.