PubSubHubbub is now enabled on all WordPress.com blogs and is available for your own WordPress powered blog through the PuSHPress plugin. Get thee real-time enabling folk.
Resistance is futile. Prepare to be assimilated, Asia. (Facebook.)
HyperTwitter is semantic hashtags on Twitter. Associate hashtags together and then performer searches. Clever. Though you might want to create a special Twitter account for doing the associations rather than sending these commands through your main Twitter account.
Google’s Living Stories code has gone open source. Now you can host news stories that develop over time.