A few weeks ago, a coworker pointed out Mosso, which bills itself as “The Hosting Cloud”. Looks like a really interesting service – basically like shared hosting that will scale forever; no need to worry about individual servers, etc.
If you are just hosting a generic php/rails/etc site that gets a lot of traffic, it looks like this would be a pretty sweet (and affordable) solution. Unfortunately, most of the stuff I do (both personally and at work) is too complicated to host on this – ie, it requires third-party software like solr or other java apps.
If anyone has tried it out, let me know how it went for you!