Interesting post from the Sharepoint team: http://blogs.msdn.com/sharepoint/archive/2008/12/05/announcing-the-wsrp-toolkit-for-sharepoint.aspx
The Web Services for Remote Portlets (WSRP) Toolkit has been released on the MSDN Code Gallery (here). This basically makes data from your Sharepoint lists available to other vendors' portals too.
Here's a quote from a related article on PC World:
Java-based portals such as BEA Aqualogic, IBM WebSphere and SAP NetWeaver include the ability to consume WSRP code. By using the new tool, developers can now produce SharePoint data and portlets natively on portals from these vendors, Microsoft said
Yet another reason for ISV's to continue adopting Sharepoint as interoperability has just been taken one step further!