Microsoft and Mozilla declared their intention to advance WebSimpleDB and their preference for it over WebDatabase(which itself is getting renamed to WebSQLDatabase) and WebStorage.
WebDatabase will be frozen in terms of its current API and likely stay at the SQL dialect of SQLite 3. WebSimpleDB has taken on the mandate of the WG to create a small and general set of primitives for building various rich JS libraries. WebSimpleDB is heavily influenced by Oracle’s experience with Berkeley DB.
Stay tuned here for more on this topic.