You might be thinking of these technologies in too myopic a form, I suspect. Instead of thinking "online diary" and "CNN headlines", think of "sophisticated content management system" and "mechanism for keeping track of thousands of different information sources in a single place".

For example, I have been talking with a client about having a private weblog area where each of their customers gets their own "category" in the weblog, and that within that category, each project or project phase is its own base article. Said customer and client can then have an interactive dialog that's archived and searchable right there in the (password protected) weblog, and both client and customer can also use an RSS reader to instantly know when a new comment has been added in any of the discussion areas.

For your interest in virtual companies serving clients, wouldn't it be nice for your virtual colleague and client to interact within an environment that you can also track and that archives more gracefully than email? You could head off any potential problems early and everyone on the team could be more aware of overall progress and attain greater levels of synergy.

My clients aren't generally taking the time to crawl through weblogs...

Then you haven't visited any well-organized weblogs. A weblog is like any other tool, in that it requires some self-discipline and organization to make it truly useful, but once it's all set up, it's a breeze to explore and identify desired materials. Plus teaching them how to get to a specific page once then bookmark it isn't too challenging. :-)

... unless you're an individual consultant or author trying to establish area expertise leadership, or you just enjoy writing and sharing while possibly creating an affiliate click-through income stream.

Actually, I would suggest that establishing area expertise is something that I suggest every single entrepreneur should be quite interested in learning more about. That's the long-term career-building side of things.