Yes, we're serious about RSS! (Jeremy Zawodny's blog)
Earlier today, Dave and Tantek took a bit of time out from Technorati to visit Yahoo and talk with a few of us about attention.xml. As anyone who went to Gnomedex or Web 2.0 knows, the idea of sharing "attention metadata" among various aggregators and applications is gaining some traction. Heck, Steve Gilmor sees it as the standard necessary to prevent a sort of vendor lock-in in the RSS aggregation world.
Y! Inc. の Jeremy 氏と Technorati のメンバーとで RSS に関するミーティング、ってな記事から、attention.xml というオープンスタンダードなフォーマットの話題。
Developers Wiki - attentionxml
Attention.XML is an open standard, built on open source (see XOXOSampleCode) that helps you keep track of what you've read, what you're spending time on, and what you should be paying attention to.
XOXO という XHTML を利用したフォーマットで、RSS アグリゲータ間の未読情報や、リンク先のクリック情報などを exportable にしようというプロジェクトなようです。