Oracle WebCenter is Oracle's "next-generation user interaction environment". It contains some “Web 2.0” functionality like Blogs, Wikis and discussion forums and (like Oracle Portal), a portal framework with development tools, a number of portlets (some in common with Oracle Portal), and a content management solution.

Even though the product functionally overlaps Oracle Portal somewhat, it has been re-engineered from the ground up as a “pure” Java product, supporting the available standards (JSR-168 for portlets, JSR-170 for content). Through the JSF-Portlet Bridge, you can “portletize” a JSF application (subject to some limitations, of course). It does not depend on PL/SQL (like Oracle Portal does) and does not support PL/SQL portlets natively (only through the Federated Portlet Adapter).

Oracle has announced that WebCenter will be at the center of Oracle Fusion Applications, meaning that every Oracle Fusions Applications user will be using Oracle WebCenter as their starting point.

Pro
With the WebCenter Extension for JDeveloper, you can easily build portlets taking full advantage of the many sophisticated components in JSF Faces.

WebCenter comes with a high-end content management solution (Oracle Web Content Management – from the Stellent acquisition) as well as a bundled Secure Enterprise Search license.

Release 11g will come with very useful pre-built application called WebCenter Spaces that allows you to set up a collaborative workspace.

Con
WebCenter is intended for enterprise level customers. It is not on the official price list in the Oracle online shop yet, but at Oracle OpenWorld 2007, Oracle indicated that it would be a $50,000 per CPU option on Application Server Enterprise Edition (which is itself $30,000 per CPU). This license includes Web Content Management and Content DB. If you do not have this budget, you should look at Oracle Portal instead.

Versions
Current production version is 10.1.3.2.0.
WebCenter 11g Tech Preview 4 (with lots of interesting new things) is available for download on the OTN WebCenter page.

More Info
The WebCenter team has a blog at http://blogs.oracle.com/webcenter.

There is more information, downloads, webcasts etc. in the Web 2.0 Resource Library and on the Official WebCenter page on OTN. Oracle presented the product at Web 2.0 Expo 2008 in San Francisco, April 22-25.