Why do the descriptions of GitHub repos not always show up in the Repositories tab?

Question

When I find a GitHub project that I like, I often go and look at other projects by the same author.

Generally people have a multitude of projects, so I skim down through the list, reading names and descriptions. I'm much more likely to actually look at the repository if the description is displaying. However, sometimes the description does not display on wildly popular repositories:

As you can see, vim-pathogen is wildly popular, but the description is not showing. This is in spite of the fact that the repository has a description, and in fact seems to be his most popular repository:

What's going on here? Why do the descriptions get dropped off in the Repositories tab?

Answer 1

On each user profile it will only show the commit chart and description for the last 15 recently active repositories. Those outside the top 15 will not show that information.

It probably has something to do with performance, and GitHub chose 15 repos as the cut-off point.