This seems to be a season of "proposals" by open source vendors to attach pieces of their code to a larger foundation. It sounds promising, but the benefits for you the customer could remain far off.
Earlier last month, ECM vendor Nuxeo proposed to contribute its Content Repository to the Eclipse Foundation. This after they dropped support for Java Content Repository (JCR), a repository spec that didn't really take off spectacularly, but was arguably more successful than most other standard related initiatives in this space. Nuxeo's contribution, named Eclipse Enterprise Content Repository Project (ECR), is CMIS enabled (incidentally, you can also access JCR via CMIS), and provides an opportunity for Nuxeo to compete with Alfresco on the CMIS bandwagon.
Both these proposals appear very attractive on the surface.
Nuxeo's contribution hopes to evolve into a reference repository implementation that makes it easier for others to focus on developing content-centric applications without worrying too much about the underlying repository. In doing so, it assumes that the underlying repository no longer provides any differentiation, and therefore essentially can be abstracted away. I've seen enough ECM and WCM implementations to argue this is not always the case.
Rave on the other hand wants to become a lightweight portal type container, but without the legacy of heavier-weight technologies such as Java Portlets. To achieve this, the project aims to integrate many other existing initiatives, and build functionality not yet present in those projects. In doing so, it risks itself turning into something that is as heavy as the current breed of Portal technologies that it wants to replace in the first place.
These are very early days for both these proposals. Nuxeo has just expressed its intention to contribute while Rave is in incubator stage. It will be a while before these reach a stage of maturity where they can be of much use to you the customer. Even if they provide technologically superior alternatives to other existing options, there are other reasons, often non-technical, that define the success of such initiatives. A lot depends on how other vendors -- mostly bigger ones -- support them. Unfortunately, we don't have a good history of vendors collaborating on such initiatives.
So for now, they are probably more useful to respective vendors, since such announcements tend generate goodwill and visibility without spending a lot or marketing dollars. But for you the end users -- as I explain in "What happens when a standard dies?" -- you should carry out similar due diligence even when a new standard (or technology) emerges.