At some point before long mashups will start becoming more utilitarian and less one-off novelties. Currently one of the more useful utilities built on web APIs is the blueorganizer Firefox extension from adaptiveblue (a ProgrammableWeb sponsor). It’s a “smart bookmarking” tool well suited to managing links related to products and media — books, movies, music — where you catalog items you own, make notes on products you want, tag, search, and compare prices (because it understands structured product data from supported sites). The just released version 2.5 has received a lot of press — for a good detailed review see Brian Benzinger’s Solution Watch summary.
What is interesting here from an API/mashup point of view is that it uses APIs and data from over a dozen sources including eBay, YouTube, Yahoo, Google and Flickr. Sometimes it uses an API and sometimes screen scrapes. For example the synchronization from any computer service is built on the Amazon S3 API for data storage services but the Cafe Press data is scraped. For a data-centric utility it’s not surprising to see so many sources in use and there will surely be more functional mashups like this to come.