One of the tests I'm currently trying is something I haven't done in a long while so I'm a little rusty. Using public blog networks and spun 2.0's with spammy tiered links to see if they still rank me in medium - low keyphrases. Been a while since I've had to write in spintax for backlinks but I would like to be pointing them at a site with some decent content say a 5k homepage with a couple of 1-2k pages for long tails and some decent media on there. But if/when the site gets slapped for shitty links I wonder if I can take that content from that domain and post it up again on the new domain once it leaves the Google index. Anyone know how long they hold a cache for or has experience doing this?