The necessary components of a mash-up according to the panelists are AJAX or a similar client-side technology, APIs in the backend (or RSS and/or scraping if need be - although some people argue scraping isn't truly Web 2.0), and a lot of work on the UI and data sets by the developer(s). Paul Rademacher mentioned there is still a lot of work to be done with the technologies - e.g. authentication. So it's early days yet for mash-ups on the Web.

As for mash-up business models, some of the suggestions were: advertising, lead generation and/or affiliates, transactional, subscription. [Full story at ZDNet]

I wrote up some notes I took at last week's Web 2.0 Conference, on the workshop Mash-ups 2.0: Where's the Business Model?. It was an enjoyable workshop, although I hope in a year's time we're able to look at business models for mash-ups that don't include maps ;-)

btw this post on R/WW is a blatent copy of Jon Udell's strategy in dealing with writing at two separate places online. I've been wrestling with this over the past month - how not to confuse people by having two blogs on the same general topic. R/WW is my hub of online activity, my online avatar in a lot of ways, but ZDNet helps pay my bills. So let's try this and see how it goes.