どうやらPosterousに記事の下書き保存機能が追加されたらしいです。

Posterousがますます便利になりますねぇ。

個人的にはテンプレートが早くJavascriptに対応してほしいところ。そうすれば本当に隙のないサービスになるはず。

Posting isn’t always spontaneous and wireless connections can be wonky.  Today, we’re releasing drafts so you can save your work for later and prevent lost posts.
To create a draft of your post, just hit the Save button from within our Web Editor.  You can publish a draft by clicking on the Publish button – your post will be autoposted as normal according to your settings.

After saving a draft and hitting the Cancel button – your browser’s back button will work just fine too –  your draft will appear in your list of posts appended with a ‘- draft’ label.

引用元: Write it now and post it later: Drafts now on Posterous – The Official Posterous Posterous.