Sphinx and full text search engines
Great intro and springboard article from the Register if you don’t know much about Sphinx on the smarter, scalable way to do full text search these days. All the cool kids are using it (and with good reason).
Sphinx and Rails goes together pretty much like chocolate and peanut butter these days and we’re using it on at least two production projects at AI, as well as it being a favourite of mine for personal use.