It seems like they paywall documents based on the number of views they get.Its really wonky with what is pay walled and what is not. I've found copywrited material that was free to download, and then court document transcripts where I needed to pay. Then they have this weird system where you can download more if you upload pdfs, leading to a ton of corporate slideshows and other inane shit being uploaded,
Here is another site that I have not heard mentioned yet: Newgrounds. I have no idea of there has been a tank in quality or not, but I do know I never see anyone talk about them or link stuff from there anymore (or maybe I'm not 12 anymore, living in the suburbs, listening to Linkin Park, watching DBZ, see copypasta below). When something from Newgrounds is linked, its usually a Youtube video recording. HTML5 and the death of Adobe Flash has probably been the biggest contributor to their downfall.
FACT: NEWGROUNDS WAS FUNNY WHEN WE WERE ALL 12 LIVING IN THE SUBURBS LISTENING TO LINKIN PARK WATCHING DRAGONBALL Z DRINKING PEPSI WHILE PLAYING HALO CO-OP ON THE EASIEST SETTING DURING WHICH WE CONSUMED DORITOS AND LOOKED AT PAINTBALL GUNS ON EBAY IN INTERNET EXPLORER CONNECTED THROUGH AOL ON A 56K MODEM BEFORE HOPPING INTO OUR BALDING FATHERS' LATEST MIDLIFE-CRISIS-IMPULSE-SPONSORED JAPANESE-BUILT SUV TO HEAD TO THE MALL AND GET MORE SKATEBOARDING SHOES AND THIRD-RATE IRREGULAR LEVIS AND MOUNTAIN BIKE PARTS BEFORE HEADING HOME, VOTING DEMOCRAT AND MASTURBATING TO THE LATEST SEARS CATALOG WHILE HUFFING PAINT IN YOUR GARAGE BEFORE TALKING TO PEDOPHILES ON AIM PRETENDING TO BE WHATEVER CAMWHORE THEY'RE RANTING ABOUT ON MYSPACE WITH A MATRIX QUOTE/ANIME CHARACTER NAME/TRIPLE SIX-ASTERISK-PARENTHESES-SURROUNDED SCREENNAME BEFORE HEADING TO YOUR SUPPOSED "GOOD SCHOOL" IN THE MORNING TO BUY MORE POT TO SMOKE DURING YOUR COUNTER-STRIKE LAN PARTY WITH JIMMY AND THE REST OF HIS FRIENDS TAKING RITALIN AND ADDERALL AND PROZAC EIGHT TIMES A DAY BEFORE TAKING A CASUAL PASS AT LOCAL, STATE OR NATIONAL GOVERNMENTAL FIGURES, LEGISLATURE, OR STRUCTURE TO APPEAR EDGY AND INTELLIGENT IN FRONT OF YOUR BUDWEISER-SNEAKING, LIMP-WRISTED, NEAR-TO-COLUMBINE SOCIOPATHIC "DEEP" FRIENDS WHO PLAY THE VICTIM WHEN THEY START LOSING ARGUMENTS SIX DAYS BEFORE THEIR BOTCHED SUICIDE ATTEMPT SIMPLY BECAUSE SCHOOL TRAMP NUMBER TWELVE WOULDN'T GO UNDER THE BLEACHERS WITH THEM TO LET THEM GET TO SECOND BASE BEFORE THEIR THIRTEENTH BIRTHDAY.