MediaWeek in the US has reported on the latest research data from Nielsen that shows mobile Internet usage growing exponentially, largely due to the increasing number of 'smartphones' such as the iPhone. However, despite the high level of expectations for this sector, the report says that only a quarter of wireless subscribers logged onto the web via their mobile devices in July.

The Nielsen research says there were 56.9 million mobile web users in the US by July 2009 - up 34% year on year. However, an earlier Nielsen report at the start of 2009 said there are almost 225 million total mobile subscribers in the US, which means that mobile Internet penetration is about 25% of the market and still trailing PC-based web usage.

The demographic profile of the mobile Internet sector shows that teens and seniors are pushing the growth in usage as they enter the market. The article says that Nielsen's data showed a 45% surge in usage amongst teens 13-17, as well as a 67% spike amongst users aged 65 and older. Males still dominate the sector with 53% of the market but the female audience rose by 43% in July, compared to a 26% growth spike amongst men.