A single login has been proposed and is being added to MediaWiki. This may be a first step to an interwiki identity standard, equivalent to real-world w:passport security features that make it hard to pretend to be someone else, e.g. a political opponent, which would be a good thing since interwiki identity standard would almost eliminate the identity theft vandalism, which can be very nasty
Trolls assert that this will be used mostly to support the sysop power structure in their attempts to assign alleged and collective identity to others, those who they typically label "trolls". In effect, the primary use of this feature will be outing of those who choose not to use it:
The Lowest Troll asserts that this will be used for identity consistency between Development Wiki, Research Wiki and Publish Wiki which is a good thing for identifying those users who consistently submit high-quality well researched, concise and well referred information from the seedy characters that may be paid trolls or other malicious or careless users that aim to or accidentally lower the grown trust (or credibility in language that the majority of us understand).