Microsoft has announced plans for a single sign-on for its Windows Live services and making it possible for users to sign up for an ID from a mobile device.

The Windows Live ID concept is to allow users to unify multiple sign-ons through a single ID and password that will link all the various Windows Live services, such as e-mail, instant messaging, blog hosting, and security – and no doubt application sharing or network programs in the not too distant future.

Microsoft adds mobile, single sign-on to Live ID

In my mind, the idea of being ‘always on’ will mean you could not only keep in constant contact with your friends via instant messenger, but potentially use Hotmail in the same way as you would use a Blackberry.

For simultaneous viewing, Microsoft hopes a user would be ‘logged in’ on Windows Media Centre watching IPTV in their lounge, with a laptop on their knee and a mobile in their pocket. Knowing which advert someone has seen on TV, and then searched on their laptop, would mean that as you walk away you could be re-targeted with the next sequenced advert on your mobile phone. Advertising interplay across channels is the essence of the race behind the Google and Microsoft ad server technology acquisitions this year.

The idea of feeding content or advertising to a 2” screen has huge potential, especially as it is the one device you always have with you and constantly connected. Talking with a gaming client earlier today, we discussed the concept of a user using mobile messaging to be kept up-to-date real-time of where a friend was at within a game on Xbox 360, knowing levels and scores and seeing else was playing and being able to respond direct to their friends’ Xbox 360 with ‘hold on, will be home in 15 mins’.

As people are becoming increasingly familiar with the GPS capabilities or even the mere triangulation of mobile phones to pinpoint a user’s exact location, from an advertising viewpoint, knowing where they are at within a purchasing lifecycle is only part of the concept of behavioural advertising. Knowing the device they are in front of as well as other user environmental issues will allow the relevant advert and the type of response anticipated – which will vary greatly between devices such as TV, laptop and mobile due to the interface – but be further enhanced in knowing their physical location.

So this could move from a MMS message of ‘thanks for the order online, here’s a coupon barcode for next time you are in the shop’ to a specific ‘here’s a voucher for the shop that is currently 50m from you’ and then linked to a map with talking directions, as someone walks down a street, unbeknown to them it was a direct result of responding of seeing an advert on TV, searching online and then visiting the advertiser’s site a few days earlier…