It was great for rap lyrics - which makes sense because it's a heavily lyric-centric genre. Sometimes the artists themselves would provide annotations, people would provide context for veiled references, etc.
So to me it makes all the sense in the world that they struggled to expand beyond that niche. The idea that the rap lyrics site would expand into annotating speeches or acts of Congress just doesn't scan.
Yes the value of the site was much more clear when it was primarily a way to demystify references and slang in rap lyrics - in the same vein as Urban Dictionary.
But since then rap lyrics have gotten simpler and the site has expanded. It's interesting to compare early reactions from artists getting their songs annotated to its place in rap today.
"Rap Genius dot com is white devil sophistry" - Kool A.D., 2012
So to me it makes all the sense in the world that they struggled to expand beyond that niche. The idea that the rap lyrics site would expand into annotating speeches or acts of Congress just doesn't scan.