At this point, there isn't a whole lot to say about the announcement (not that that'll stop us in the press from saying a lot). Much will depend on the license HP chooses for webOS and on the project framework that HP adopts for its semi-discarded mobile platform.
Reviewing the scant info that HP has provided so far, here's something that stood out for me, a remark in the Hello World post on the webOS developer center blog: "We recognize that there's a larger open source community of which we will now be a part, and are excited by the future now open to us."
See, that's really isn't how it works--companies don't simply heave a sack of code over the fence, and watch as it's swarmed by value-adding open source community members. The software developers and hardware makers that HP may be counting on to make this work have to find reason enough to invest in the platform that HP has just deemed fit for (at least partial) divestment.
Also, open source software always played a large role in webOS, starting with the platform's Linux core, so HP and webOS was already part of the open source community, though perhaps they didn't see it that way. If that's the case, it's not a good sign.
relevant morsels from the press release:
"HP will make the underlying code of webOS available under an open source license. Developers, partners, HP engineers and other hardware manufacturers can deliver ongoing enhancements and new versions into the marketplace.HP will engage the open source community to help define the charter of the open source project under a set of operating principles:The goal of the project is to accelerate the open development of the webOS platformHP will be an active participant and investor in the projectGood, transparent and inclusive governance to avoid fragmentationSoftware will be provided as a pure open source projectHP also will contribute ENYO, the application framework for webOS, to the community in the near future along with a plan for the remaining components of the user space.via HP to Contribute webOS to Open Source."