I am planning to create a private web site where people of a very specific target group would keep private stuff.
I am between two major roads for this.
-Build a trusting and personal relationship with the members. Above this apply htts sitewide and create a strong privacy agreement.
-Implement client side encryption with keys that only the user will know and have the responsibility to maintain.
To give a similar example think of that: Keeping a daily journal on the web. Either i would sent my text already encrypted or i would rely on the privacy of the site.