Writely is no more -- it's now been renamed to "Google Docs" and packaged with "Google Spreadsheets" (just in time for Office 2.0). TechCrunch has the story here, where Arrington notes that Google isn't the only game in town:
Notably absent is the ability to embed spreadsheets directly into writely documents, a feature already offered by Zoho, which has been furiously updating its own office suite (Google says this feature is coming).
Missing from Spreadsheets is the abilitity to post as JSON, which would have been brilliant for controlling mashups.