- Events -- enabling portlet to send and receive events and perform state changes or send further events as result of processing an event.
- Shared session attributes -- allowing portlets to share session attributes beyond the current web application.
- Shared render parameters -- allowing portlets to share render parameters with other portlets.
- Resource serving -- provides ability for a portlet to serve a resource.
- Portlet filter -- allowing on the fly transformations of information in both the request to and the response from a portlet
Dave Brondsema gives a more complete review of features on his blog. Other comments from the blogsphere also look positive:
Since version 1.0 a lot has happen in portal space. The spec has been put through the real life tests and quite few "gaps" were identified that needed immediate attention. Probably the single biggest complaint was lack of inter portlet communication (the spec only provided portlet session for that purpose). Naturally Portal vendors filled up those gaps by providing vendor specific solutions but then it led to the situation that portlets which use those solutions are again non portable...