Even though I love the Web 2.0 movement and applications, there is by far a shortcoming on this movement that keeps it from being adopted by many. That issue is one of interoperability.
Let’s say I have a set up of Office 2.0 applications. I love all of them for specific reasons; some are stronger in some points than others. Now let’s say I want to integrate these applications together. In order to get my Zoho Word Processor to work my del.icio.us I only do one thing. Either I can use their respective APIs and try and create a mashup, but that still want provide the opportunity for them to talk together the way I want them to, but that will result in quite a mess as I add more applications. Or I could submit a request and wait for ever and a day until the “beta” stage clears and then maybe they’ll respond.