IFA (Identifier for Advertisers) is something new in iOS6 and resembles a unique ID that can be passed to advertisers to anonymously keep and track user context (and hopefully provide a better experience).
My questions come particularly from the web-development domain (i.e. mobile browser/javascript):
Is there any equivalent for IFA on Android (if yes, in which OS version does it exist)? If there is none, what is the common alternative - is it just a cookie? If so, what is the right technique to implement it (I guess 3rd party cookie / security is something that should pop-up in the context)?
Actually any well-working/well-formed way to track user context for ads relevance will be mostly welcomed.