Microsoft - the company which shot the Liberty Alliance?

News that HP and Mastercard have joined the Liberty Alliance was almost overshadowed by Microsoft's expressed interest in joining.

Although Redmond has been teasing the organisation with the possibility of it joining from day one, there was always the issue that Sun was a founding member.

The main aim of the alliance is to create open and federated single sign-on identity standards. The only problem is this treads quite heavily on the toes of Microsoft's Passport.

So not only does Microsoft have to deal with having to work with an entity initiated by a company that isn't exactly its best buddy, it will also want to keep a tight hold of its technology and ensure its dominance.

For this reason it's hard to imagine Microsoft will get heavily involved with the work of the alliance. Except, of course, to ensure Passport's interoperability with any resultant standards.

And it's highly unlikely that Microsoft will ever ditch Passport or favour having more alternatives on the market. Firstly, it's not in the nature of the company to give in to a competitive alternative and secondly, it has already established a growing stronghold for the technology with customers including Egg and eBay.

So is it likely that if - and it's still a big if - Microsoft was to join Liberty, it would pass on all that it had learned in making and developing Passport for the greater good of the interconnected world? What do you think? We have our doubts.

Nevertheless, the fact that there are a growing number of high profile companies joining up and at least some indication that Microsoft is prepared to talk to Liberty bodes well for promoting consumer confidence in the notion of the single-sign-on and web services more generally.