A shock site is a site that will shrink your browser, make loud music/sound files play and flash pornographic(usually gay) images across your screen. This is a internet prank commonly used to trick new people into going to one.
Good examples are www.meatspin.com, www.lastmeasure.com, www.lemontubspin.com
new person:hey, how do i get to the posting screen for this forum lulz
guy:just go to *disguises link to a shock site as a link to a help topic*
noob: gee thanks
*a minute later*
noob:hey you asshole you gave me a virus!