Advertising-funded MVNO Blyk has increased its UK subscriber base to 200,000, double the number it had in April, reports Reuters. The company launched in September 2007, offering free calls and text messages to 16 to 24 year-olds in return for users accepting advertisements from the likes of Coca-Cola, L’Oreal and Sky. Reuters adds that CEO Pekka Ala-Pietila told an analyst briefing yesterday that Blyk achieved the highest response rates for the lowest cost of any advertising medium; 25 percent of those who receive ads respond to them, costing advertisers £0.50 per response.

Blyk plans to extend its service into the Netherlands later this year and will launch in Belgium, Germany and Spain next year. Reuters notes that Blyk’s operations – the world’s first mobile service funded solely through advertising – are being closely watched by traditional mobile operators facing falling voice revenue. Mobile advertising is considered a serious potential new revenue opportunity for operators worldwide.