I find Twitter to be the ideal medium for posting short messages, especially with its GTalk integration on a Blackberry, its always on and with me.
But I have found it difficult to categorize messages. Hashtags, a new service, aims to cure that shortcoming. Mark any word in a twitter message with ‘#’ and the service would pick it up. This is like tagging for twitter messages, would help group and track messages with a certain tag.
But it does seem a little weird to have metadata(atleast 1 char) within 140chars worth of text. And possibly more if the tag does not appear naturally within text.
I have been using this for the last couple of days to note quotes from two books of Nassim Nicholas Taleb. You can follow me on Twitter if you want to cover the highlights of these books without effort! The hashtag I am using is #bookquote. Let me know if you would like a tag on a per book basis.