Your basic problem was content management: being able to produce and distribute updates quickly, plus have a ready made search and index for all past updates. Agreed, email is a horrible toolset for this.
Curious first of all whether Blogger offers you any kind of privacy or security, so that all of your client updates aren't all public, not to mention immediately Google-indexed.
Another alternative you might look into is setting up a free Wiki hosting for each client. We use that for some dedicated internal projects. The advantage here is that it's private and both developer and client have a user-friendly toolset to track changes over time, create on the fly documentation, and manage active projects.
I haven't used this one specifically, but take a look at Team Wiki as an example. I think there are probably a few options out there that allow you to set up a wiki set just like you set up a blog, and some of them either totally free or relatively low-cost.