When looking at the world of web 2.0 I think that you can categorize the companies and products into a few different areas:
Sites that create or originate content but do not share them openly are what I call data silos. Many of the "Web 1.0" companies fall into this area. Examples include: Match.com, Career Builder,
Web Service Providers :
Sites that expose functionality and data openly are what I call web service providers.
Examples: Google Maps, eBay API, Flickr
Data Silo Aggregator:
Sites that unify data from separate data silos into one common view.
Examples: AP News Wire (offline), Indeed.com, Oodle
Web Services Aggregators:
Sites that unify separate web services and/or data silos.
Examples: Chicago Crime Guy, Weatherbonk, Craigslist/Google maps mashup
If you want to see a more detailed break out of companies and where I think they fall please go here. It's in wiki form so please check it out and add.
I'd also love to get people's thoughts about how they are thinking about categorizing the web 2.0 world.