Switching to Mailpile – the search and privacy-focused webmail client
blog.bytemark.co.uk
blog.bytemark.co.uk
I actually met @HerraBRE in Reykjavik last month and talked about privacy and ambition for the software, but couldn't really fit it in without making the article a lot longer.
He's written his own search index and database for the whole thing, it's a really impressive piece of work.
Anyhow, I'd heartily recommend giving it a try.