del.icio.us, Web 2.0 and centralized vs. decentralized services

Yesterday del.icio.us, the well known social bookmark service, has been bought by Yahoo. This brings me to share some thoughts I had recently about the thing that everyone calls »Web 2.0«.
Although probably nobody can provide an exact definition on what Web 2.0 is, it's mostly surrounding »social software«, i. e. web-software that is not organized as top-down-communication, but as communication between the users.
The most common example for social software are probably wikis and blogs. What I always saw very critical is that centralized services like flickr and del.icio.us are so popular in the blogosphere and the internet community. They are often called »Web 2.0« as well, although they work completely different. My vision of a free net is a different one.

Now with yahoo buying del.icio.us, the two probably most popular »Web 2.0«-services belong to the same company. The problems with this are obvious: You don't know what Yahoo does with your data (Data Mining), you never know if they're gonna change their terms of use from one day to the other (e. g. limit the number of pictures/links, take money for services that were free before) or even shut down a service because it doesn't match the »shareholder value« (Remember GiMiX? That was social software as well).

In my opinion there is a big discrepance between the ideals of »social software« and letting it depend on one centralized service. I have no problem with hosters that provide free/ad-financed blogs. As long as I can trackback them with my self-hosted blog-software, as long as they can link me and as long as I don't need an account at some companies service to comment them. With flickr, this is different. I cannot add pictures on someone else's flickr-group from my own web-gallery. All the »social« aspect of flickr are completely based on everyone having an account at yahoo. Same goes with del.icio.us.

If we really want »Web 2.0« to be something that has to do with more freedom, more control from us / the users / the single person on the net, we should provide alternatives to centralized services. Alternatives that are not based on »just another web-service«, but on decentralized open standards and (at least as a possibility) free software. A fine example how this works is jabber (as an alternative to the IM-chaos of ICQ/AIM/MSN).
An alternative to del.icio.us could work like the PGP-keyservers. An alternative to flickr would be interoperability-standards to the various web-galleries (coppermine, menalto gallery), maybe some function similar to trackbacks for collective albums. If that's the direction »Web 2.0« goes, I'm really looking foward to »Web 3.0«. If »Web 2.0« means monopolies of Yahoo, Google and Microsoft, then it's not »MyWeb 2.0«.