It's the beginning of the OpenBenchmarking.org Performance Classification Index. That blog post goes into more detail about what this is, what it means, and where the lists are at. Simply put, when a monitored piece of computer hardware enters the OpenBenchmarking.org database and begins appearing several times, its performance is then compared to other like hardware and is then ranked on this index.
So if you're looking for a graphics card, motherboard, or other key components, it's as easy as looking at a simple list. Pricing information is also integrated into the lists. Due to safeguards in place and other steps to refine this data, the list is fairly concise but will continue to grow as more test data becomes available and is verified. There are also other features coming about for these performance lists as talked about in the aforementioned blog post.
Your feedback also is valued as the OpenBenchmarking.org features are refined. Any questions can also be answered in the forums.
For those new to OpenBenchmarking.org, see the welcome Slashdot blog post.
Update: Here's another new feature.