They've definitely added some lyrics to the internet that weren't previously there. Unfortunately, the rise of these aggregated ad-trap lyrics sites has also had the side-effect of crowding out better, more decentralized lyrics. Google seems to prefer these big centralized sites over the long-tail fan sites that provide higher-quality, curated and proofread lyrics.

When I search for, say, [joy division atrocity exhibition lyrics], I get 10 generic lyrics sites as my first page of Google results. But what I really want is to get a result more like this: http://www.joydiv.org/shadowplay/joyd/atrocity.html

Besides not being piled up with ads, those fan-curated sites typically have fewer spelling errors, actually attribute lyrics to specific versions of a song and note variations, etc. Of course, in the cases where I already know a good fan site, I can either go directly, or do a site: search in Google. But in other cases I have to click through pages of this junk.