First of all, I LOVE Codeivate! I think you have a ton of space to grow in as well. I think adding much more ability to segment in the leaderboard will really blow out the competitive angle of the already great gamification of my work. Keep it up!

Adding the ability to compete with my peers on a per language basis would be pretty awesome. I can already do it to a certain degree with the sortable columns, but being able to restrict the leader-board by language will compound the value of that sorbability. For example, I'd like to be able to sort within sass/scss only. That actually brings up another point, some languages are actually synonyms of each-other, like sass/scss, sorting synonyms together would be another value add.

BTW, I'll be buying a premium membership as soon as my budget allows. Love the product!