I like SEO not for its commercial application, but for the idea that you can help other people who dealt with some of the same problems you dealt with, and that you can help give a voice to people who might otherwise not have much of one.

I also like how a bit of knowledge sorta levels the playing field quite a bit.

Although the large commercial forces biasing search are going to make it increasingly harded to be heard unless you are really really passionate about what you are saying and can make others passionate about actively spreading your message.