Open hardware are boards like Ardoingo, Galileo, BeagleBoard, some Olimex boards, Littlebits. You can get schematics/gerbers and software source code and modify it.
Open Source Hardware Association OSHWA has launched a certification program (last Friday, on October 8 2016). It’s self-certification with a specification of what you have to comply to. You get a unique ID number for this design. When someone modifies the open hardware, they can/should ask for a new ID number. There is a registry of certified devices.
The medical field is difficult for open hardware because there are pretty high barriers to being allowed to develop such products. However, several new devices in this field have appeared. A device to measure hand pressure to help surgeons to learn how to suture correctly. A second project is an open source prosthetic arm design that can be 3D-printed. This design is modular, which makes it possible to use for children who are still growing so you just have to replace some parts.
Open hardware is useful for museums because it allows them to build things more custom cheaper.
PSAS: open everything space exploration project.
Arduino was split up for a while over a trademark issue, but now it is one project again.
C.H.I.P. is shipping boards. It’s a poster child for open hardware, because they really make everything available. They also develop missing pieces of software, like MLC flash support in UBI.
Google joined the Open Compute Project. They develop open hardware for datacenters, with a focus on cost and on power consumption.
Open Source Hardware projects are popping up all over on Kickstarter.
Open Source Hardware is mainly low speed designs. Higher speed designs are developed at a slower pace – e.g. the free tools (KiCad) don’t support them very well. Designs in expensive design tools can be considered open hardware, but they’re less useful because there’s a large barrier of entry for contributors (expensive license). Olimex makes new designs exclusively in KiCad. KiCad is getting a lot better because of such support.
There is an open source graphics card under development, but haven’t heard news from them in a while. Last news was that they had it working on FPGA.