Before I discuss some unique features of py3ksupport, I want to point out that right now that 56 - 60% of the top 50 projects based on downloads of their latest PyPI release support Python 3. The reason for the range is that some projects had in-development support last time I looked and since that can change underneath me I wanted to cover the possibility the data was stale. But the key point is that 8 of the top 10 projects support Python 3 and one of them has support under development along with over half of the top 50 projects.
So I'm sure the site explains itself (and the FAQ fills in gaps), but I figured I should explain some of the more unique features of the site. One is the metadata rating given to each project. Basically I wanted to shame project owners into updating their project metadata. LOTS of projects don't bother to specify the Python support metadata for their projects which makes my life difficult and is unfortunate for users. For instance, of projects bothered to specify the exact versions of Python they support then users could easily tell from the Cheeseshop (nee PyPI) whether they could use the project based on what version of Python they are tied to. I might have to do some public shaming at PyCon if the situation doesn't improve. =)
The other key point is that I personally keep the front page up to date. If a new project shows up on the front page that does not have the proper metadata specified then I personally search online to find out the status of the Python 3 support. Since I get emailed each day when this happens the situation tends to get fixed that day and will be noticed within an hour of me fixing it (the length of time I have things cached).
I'm hoping to eventually move to measuring an project's popularity based on the download rate for the lifetime of the application (instead of just the latest release) to give a more accurate reflection of how popular a project is.