(ShareCast News) - The People's Operator, the mobile phone company led by Wikipedia founder Jimmy Wales that allows users to direct 10% of their monthly bill to a charity, revealed continuing strong growth in the UK and first new subscribers in the US.TPOP, which floated on AIM last December, has seen its UK subscriber numbers rocket more than threefold to 47,500 since the start of the year, and increase 58% since final results were published in mid-May.These are in line with forecasts from house broker FinnCap for a full year target of 69,500, with interim results on 29 September to provide more details on sales and profits.Average revenue per user (ARPUs) for pay-as-you-go (PAYG) are ahead of £6 expectations at £10.89 and pay monthly (PAYM) subscribers at £13.63 also comfortably above the £12.50 estimate.The average cost of customer acquisition has been considerably below industry standards at approximately £8, versus industry peers generally allowing a cost of over £130 per subscriber.Following the 21 July launch of the US platform with carrier Sprint, so far roughly 5,000 subscribers have committed to date after two months of "soft" marketing, also in line with expectations.Executive chairman Wales was pleased that subscriber statistics outperformed the accepted market norms."The US launch has been well-received and we are encouraged by the high level of interest shown in these early days. We are confident that this strong development will continue during the remainder of 2015 and in to 2016."He said management were are also pursuing a number of exciting initiatives that we expect to make a "significant contribution" commercially, financially and strategically."The US launch serves as a reminder that TPO has a product that is relevant in numerous geographies."The TPO.com social network, which the company hopes destined to be a strong sales channel, is growing well with 17,000 users to date and 79 causes signed up, including Save The Children and World Wildlife Fund.