From the press release:
HP plans to continue to be active in the development and support of webOS. By combining the innovative webOS platform with the development power of the open source community, there is the opportunity to significantly improve applications and web services for the next generation of devices.In my opinion, this was the best thing HP could have done with a dying web-oriented mobile operating system. Now that it's open-source, other hardware manufacturers can utilize the OS to make cheap tablets and such. If webOS gets popular, it will also incite app developers to support it.
HP CEO, Meg Whitman said in an interview, when asked whether the company will continue making tablets, "The answer to that is yes but what I can’t tell you is whether that will be in 2012 or not... But we will use webOS in new hardware, but it’s just going to take us a little longer to reorganize the team in a quite different direction than we’ve been taking it in the past.”
So there will be a new webOS team in the company, but they will not continue in the smartphone business. If you purchased an HP TouchPad for $99 (US only), it was the deal of the decade. It may get more expensive later on.