Most people just rely upon the drivers provided by their Linux distribution or the distribution's package repository. A good chunk of binary blob users are obtaining the Linux driver from the manufacturer's web-site.
The use of GPU compute technologies (OpenCL, CUDA, etc) still is not widespread on Linux. In part this is due to the open-source drivers lacking the compute support. On the AMD binary driver, right now the Stream/compute support is not bundled with the Catalyst package itself, but that is changing.
Between TV-out, multiple display heads, output hot-plugging, and GPU power savings, most are using multiple display heads/monitors followed by power savings functionality. (Sadly for most open-source drivers, the GPU power saving features still are not automatic.)