Our adoption model is to pass through a phase where content is separated into a key hosted by a site like Facebook (on the link), and the encrypted text on a content server like priv.ly. That way it is readable when they click the link, but priv.ly cant see it unless the link is clicked. Over the course of time we will transition away from this model because the ability to read the content without clicking through should be enticing, and we will prompt for installs every time they do click.

Usually GPG is used to secure email transmission, and not storage. There are examples out there of storing your email GPG-encrypted, but you would have to leak at least some information to have useful things such as indexing for search on your emails.

Wah?

I use GPG to encrypt data all the time. For example all backups I do are via http://duplicity.nongnu.org/ (its also super convenient)

Additionally all emails that are GPG encrypted are stored that way with all the mail clients I know of (that is, they just keep the mail the way it is,decryption is in volatile memory only). So yes storage is encrypted too!

Yes it also means search only works on sender/subject. Eventually you can have an index that is GPG encrypted and works once decrypted, no technical issue here.