The smart link builder who finds sites that are not being over run keeps them to themselves. The foolish link builders post their links in some thread like "200 blah blah backlinks here" and gets "Thanks bro" and "really good find" comments from strangers that are about to pee on their work of finding them since the sites are now out in the wild and about to be drowned.
Yesterday a very Popular SEO Software company decided to make everyone they could into stupid link builders. In one of the worst concepts ever they determined that its actually in their best interest to make sure everyone has an incentive to share their links with everybody they can find so that multiple webmasters now who had more lenient controls about leaving links (because they were not getting hammered) will have to shut down their policies and lock down their sites.
This stands to affect everybody even if you don't use that software because once a person using their software finds a nice resource they are now given incentives to share it with hundreds and thousands of other users and in a way that with a click of a button each of them can now create hundreds and thousands of profiles to spam the life out of those sites.
Once your resources gets on this list webmasters will have to respond but even if they don't the resources will be diluted because PR or whatever else search engines use is not infinite and will get weaker and weaker running through that site.
Finding real link juice just go t harder but they all think its a feature worth being happy about. Crowd sourcing is a perfectly stupid concept for link building. Its like having a semi private pool and inviting everyone in your city to use it. Its a self defeating practice.