The one that most readily comes to mind is the efforts of the Spider-Girl fans to keep that series alive, which they managed to do for something like 70 issues or so. And they did so both by being organized and being smart. They not only got sales to increase time and time again to pull that book back into profitability, they also did outreach to bookstore chains and book clubs and so forth to pimp and push the collected editions. They were truly the most organized and most successful of these sorts of campaigns–nobody since then has even touched them. Their efforts were remarkable.