The best part is that this is all available freely as bittorrents. It'll take you many hours to wade through it all, but the gems in there make it worth the trip.
What I hear on these albums really runs a wide spectrum of music, both in terms of genre and production value. Some sound like a kid with his iMac and a mic. And there's others that sound just as produced as any mainstream studio release. Of course music is about more than how expensive of a mic you used: you'll hear "Good" songs in both groups.
Besides the fact that almost all of these tracks are 'Rap', if there is a unifying feature here it's that the songs are about nerdish things. You'll hear tracks reciting Pi, talking smack about operating systems, and games from Super Mario Bros to Warcraft and Dungeons and Dragons. Much of the Post Dre rap you've heard celebrates the 'Gangsta' lifestyle. Personally I find much of this very hard to take seriously. Likewise, much of the lyrics just get campy. It's like a Weird Al mad libs lyric, where the rapper tries to rhyme whatever techish things pop into mind. Sometimes it works. Sometimes it doesn't.
MC Hawking is a great example. His track essentially an MC Battle style rap that relies on the synthesizer voice gimmick. But damnit it actually works. The lyrics are tight and amusing. I wish the hook was stronger, but thats a track I'll enjoy listening to.
Monzy's 'So Much Drama in the PhD' works as well. 'I run gmake and gcc / and i ain't never called malloc without calling free'. The parts come together really well. He might not be the best rapper you've ever heard, but I really enjoy the track. But the lyrics are ultimately that of a novelty song. Very entertaining with a good beat, but very niche.
Ytcracker's "In My Time" is just a fantastic track. You'll be hard pressed not to tap your foot. His lyrics are less obvious then most anything else on the rest of the album. He might be referencing the Atari 2600 or downloading porn to a USB pen, but you could play this track outside a compilation like this and it works. He's probably my favorite on the set. I had to snag more of his stuff from his web site, and it was interesting to see that his work is actually progressing. Having mined the most extreme end of the tech/geek world, his last few songs are stronger for it.
Another common theme here is liberal use of samples. Almost everything has samples from somewhere. You'll here the sound of Mario catching a mushroom integrated into the beats of tracks, and countless game theme songs and sound effects split apart and remixed. Sometimes it's just a gimmick. Other times it works musically. In addition to liberal use of sampling, copyright issues are a common theme in many tracks as well. Sometimes it's subtle, flippant references to downloading movies. But in the case of "Fuck the MPAA"... well, not so much in the way of subtle ;) Don't get me wrong- I got little warm fuzzies hearing sounds that i haven't heard in years, back from my childhood. But after 70 odd tracks, the novelty fades.
On a somewhat related notes, Googling a few of these artists and you'll find another common theme- the remix. Many of these artists feature remixes on their own sites done by others. Doing this definitely shows that a compilation like this is only the tip of the nerdcore iceberg.
It's also worth noting that there are a number of tracks that kinda don't fit. Foreign language stuff. Stuff that falls more into the pop category than hip hop. Some of these tracks are allright, but they feel out of place in this compilation. Like the Rappy McRapper track 'Lick Your Own Butthole Dance'. It's purely goofy silly stuff. Not bad mind you, but it simply doesn't fit. That said, I must have listened to that butthole song 10 times. It's so stupid I love it.
I sort all my music using iTunes '5 Star' thingee. Anything I rate 1-2 stars, I never want to hear again. 17 tracks here fell into that category. Anything 4-5 stars is stuff that goes into my uber playlist. I currently have 1174 songs in this playlist. Of the 4 CDs of music here, 15 songs made it to that playlist. Thats better then most music I listen to.
My suggestion- just download it. Listen to a couple tracks at a time. Don't listen to 15 in a row or it'll break you. Listening to someone rap about Warcraft and followed by one about rolling D20s gets old when strung together. But the best tracks on here stand tall, taking "Nerdcore" away from being simply silly novelty tracks ready for morning zoo radio and campus CS labs, and instead showing that the so called "Nerdcore" lifestyle can be celebrated in at least as interesting way as "Gangsta". The best tracks here do just that. Finding them is fun. A number of artists here are doing just that.
But at the end of the day, sometimes you just need to find a bit of music that you can relate to. And when you hear 'join me in the basement cuz it's warcraft patch day / time for D&D a frontalittle mainstay' day, so it's time to play D&D.... well, thats my Tuesday too. There's something odd about hearing it rapped about.