Yahoo's support of Hadoop demonstrates its usefulness in a Web 2.0 world

Tim O'Reilly has an interesting article about Yahoo investing in and supporting Hadoop, and why they may be doing this:

[Yahoo's support] indicates a kind of competitive tipping point in Web 2.0, where a large company that is a strong #2 in a space (search) realizes that open source is a great competitive weapon against their dominant competitor.

last.fm is one of those Web 2.0 companies that O'Reilly refers to. Last.fm employs Hadoop to analyze its listeners' music habits and find other users with similar tastes. Any social application will have similar needs.
The era of the lumbering desktop application is drawing to an end. I expect to spend the majority of my career programming for the web. Almost all Web 2.0 applications will be looking to take advantage of the huge amounts of aggregate data they will collect, which will make Hadoop experience more and more beneficial.