It was recently announced that Rap Genius has some pretty major financial help lined up. California venture capital firm Andreessen Horowitz is reportedly investing $15 million in the site, which uses crowd-sourcing to provide and explain the lyrics of rap songs.

In a post on Rap Genius itself, the firm’s Marc Andreessen explains that even more than the actual content of Rap Genius, he’s interested in the way that the site utilizes annotations. He explains,

“Finally, there’s the other reason – maybe even the real reason – why I’m so fired up about this idea and this investment.

Only a handful of people know that the big missing feature from the web browser – the feature that was supposed to be in from the start but didn’t make it – is the ability to annotate any page on the Internet with commentary and additional information.

Back in 1993, when Eric Bina and I were first building Mosaic, it seemed obvious to us that users would want to annotate all text on the web – our idea was that each web page would be a launchpad for insight and debate about its own contents. So we built a feature called "group annotations" right into the browser – and it worked great – all users could comment on any page and discussions quickly ensued. Unfortunately, our implementation at that time required a server to host all the annotations, and we didn't have the time to properly build that server, which would obviously have had to scale to enormous size. And so we dropped the entire feature.

I often wonder how the Internet would have turned out differently if users had been able to annotate everything – to add new layers of knowledge to all knowledge, on and on, ad infinitum. And so, 20 years later, Rap Genius finally gives us the opportunity to find out. It's an ambitious mission, and one we are proud to get behind.”

Read the rest of the letter (annotations and all) over at Rap Genius.

[via TheFader]