I agree the basic twitter.com page is like a firehose. However, I've got a few ways of stilling the flow.
I use "Hootsuite" and arrange those I'm following into columns according to interest area e.g. ESL, travel, etc. Then I only put the ones I'm REALLY following closely into each category. The conversations are threaded and if you click on a little + next to the message it brings up a preview of the real site with an image and some text.
If you want to send longers messages, you can use twextra for rich formatting too.
Another nice service is twitt.er times which gives a newspaper version of the main tweets you receive which have attachments. It includes images, a summary of the story and who tweeted or retweeted it.
Also, you can use twitpic or twitvid to upload and share pictures and videos. Twitter is also rolling out a suggested friends function (on the regular .com site).
Of course, I agree that some of these are add-ons rather than built-in features, and that Facebook is more for personal & social communication.
However, FB is not without its issues and limitations also. One of the biggest was privacy problems, which I'm not sure are completely addressed yet. For adults I guess this is less of a concern than with children who may share more on FB than they should. Also, I believe third party companies can still access your friends and friends of friends for direct marketing. Finally, all the stupid/inane apps (like Farmville) are still potential hazards.
That is why I've been terribly unfashionable and started a MySpace account. It's harder to convince friends to use it, but if you look at the new interface and some of the other nice features, it's really as good as FB. Since I have recorded a number of music tracks, MySpace also lets me share these directly from my profile both in audio and video formats. It also offers a blog where you can rant on longer if you want, and it's the second biggest network behind FB.
Bottom line, there's a place for both. It's just a question of getting them to work for you efficiently, and of choosing which to use in which context.
Posted 11th August, 2010 at http://jasonrenshaw.typepad.com/jason_renshaws_web_log/2010/08/facebook-or-twitter-or-both.html