I was looking at the challenges graph while seeking a game, and i thought of how cramped up it is . This is most noticeable when a large number of challenges are being displayed,  usually clustering the green balls. Players giving out challenges have larger probability of being in the 1400- 1800 range, while the ratings outside of this group are seen less, and thier appearance probability on the graph drops the closer they are to the 1000 rating, and 2500+ ratings. This is a bell graph behaviour and maybe the challenges graph would work better if modified towards this idea. For instance, there is a large gap between 1000-1200 on the current  chess.com challenges graph, this interval is out of the range of 1400-1800 and might not need so much space. So my suggestion is, to organize the chart to be something similar to this:

I didnt make it up to perfect scale (it was in paint), but i hope it reflects the idea.

 Making the left scale act as a bell would make the seek experience alot better in my opinion. Given the observation that most of the seeks are in the 1400-1800 range.

Regards,
Rachmanny 

interesting. i think we USED to have it that way, but we learned that actually we have a ton of seeks in the 800-1400 range and it was cramped for them. 

we're working on making the graph more useful though, so good feedback!

Perhaps each user should see a different graph with the rating axis expanded around their own rating. That's gotta be easy to code. ;-)

I took some shapshots of the challenges board at a few random times, i did aim for the busiest activity though. Ill paste some more afterwards but it seems like most of the seeks are around the 1400-1800 range.