MMO2, reporting that its customer base had swelled to 17.7 million, credited the ditching in April of brands such as BT Cellnet and Viag Interkom in favour of the pan-European name O2.
"The response from our customers... to the new brand has been overwhelmingly positive," chief executive Peter Erskine said.
And MMO2, which is sponsoring Big Brother 3, said it had handled 6.6 million text messages related to the fly-on-the-wall show.
The message total was split equally between votes for contestant eviction and requests by mobile phone users for features such as news and ring-tones, MMO2 said
One million text message votes were sent on the night two weeks ago when personal assistant Adele Roberts was evicted.
The Big Brother website has attracted 7 million page impressions related to users of WAP phones, Thursday's statement added.
Data promise
Mr Erskine said the figures showed the potential for new generation mobile devices to boost revenues.
"Mobile data is a reality today," he said.
"For the first time, content, devices and ease of use are coming together and have contributed to a strong quarter."
The launch later this year of phones that can send pictures as well as text, and of joint camera/voice handsets, would see "the momentum... continue throughout the year", Mr Erskine added.
The progress of next generation mobile devices is being closely watched by investors concerned that too much hope has been placed on their success.
Mr Erskine added: "Data is essential to mobile industry growth and from the middle of this decade it is expected to account for more than 90% of the total mobile revenue growth."
Key market
The firm's net growth in customer numbers of 292,000 over the April-to-June period was boosted by apparent success in persuading customers to take up contract, rather than pre-pay, phones.
The number of UK pre-pay users fell by 24,000, while the contract customer base swelled by 111,000.
In the German market - viewed as a key battleground for MMO2 - the firm attracted 195,000 customers to breach the 4 million mark overall.
"We were particularly pleased that we maintained our momentum in the German market," Mr Erskine said.
But Thursday's report revealed the firm was still struggling to achieve the revenues from German customers that it has in other countries.
Considering only post-pay users, average revenue per German O2 customer came in at 522 euros over the quarter, compared with 798 euros in the Netherlands, 808 euros in the UK and 1,002 euros in Ireland.
City reaction
In the City, the data received a warm initial welcome from investors, sending MMO2 shares up almost 10% to 51p in early trade.
The stock closed at 49p, up 2.5p on the day.
The shares were floated at 74p in November last year, when MMO2 was demerged from British Telecom.