O2 More, the personalised mobile marketing service operated by O2 Media, now has six million customers.

It’s reached the figure just six months after passing the two million mark. The company also notes that 93% of people open its messages within five minutes of receiving them.

New location-based app echoecho left its beta stage this week, having attracted $750,000 in funding from Google Ventures and UK-based PROfounders Capital.

The cross-platform application is designed to help customers find where their contacts are, even if the recipient of the ‘where are you?’ query doesn’t have the echoecho app. The user can also share their location with friends.

Ofcom has published a statement on its plans to introduce so-called ‘white space’ technology in the UK. White spaces are the unused parts of frequency bands that have been reserved for other uses, such as TV transmissions.

The regulator says they could be used for a wide range of applications including rural broadband and WiFi with up to twice the range of today’s technology.

Facebook is making a number of changes to its service, with improvements to its privacy controls.

It's also phasing out the 'Places' feature, which was available to mobile phone users, and will now allow users to 'check in' by adding location to anything - including status updates, photos and Wall posts.

Sandwich franchise Subway has launched a discount voucher scheme within the O2 More 'You Are Here' location-based advertising service.

Customers who've opted-in to receive marketing information will receive a MMS message when they're near a Subway store. The message will offer a discount and will contain a square barcode - a QR code - that can be scanned by store staff.