M.icroformats (including tags)
    A.jax (including Comet)
    J.SON (plus YAML)
    O.penID (plus SXIP, LID, Yadis)
    R.EST (including Atom, APP)

I'm reminded of Tim Bray's Technology Predictor Success Matrix and his appreciation of the 80:20 phenomenon. If hitting the sweet spot of achieving a lot with only a little is the main test of potential, then these five Web 2.0 technologies are all set for success.

So it's no surprise to see Tim supporting Microformats once or twice and even JSON, in spite of his, um, XML background. He also understands and uses Ajax and backs REST (in particular via Atom). Tim has not yet mentioned OpenID, instead referring to SAML and Liberty Alliance (please don't be crass by leaving a comment speculating on the reason for this...).

These MAJOR Web 2.0 technologies should form the basis of the two-way, interactive data Web or the Web-as-a-platform vision that we've all been promised.

However, they will need taking a little further this year, in order to bring them closer together and to make this vision happen in a seamless way.

A synergy between these 80:20 technologies can potentially produce much more than just the 'next version of the Web', if engineered well.

I have already discussed the Subversive Microformat, I've promoted Declarative Ajax and currently I'm slowly working up to Symmetric REST.

Next up, I'll be asking you to consider a web of JSON Microformats and ways to merge hCard and OpenID into active user personas - even avatars...

I'll tag this acronym as 'rajmo' instead of 'major', for obvious reasons.