I also thought those fb emails, and even more so the linkedin ones where people endorse you to be very effective. So I personally hated and admired them at the same time.<p>The problem for me is that those tactics don't seem to translate so well outside of the social-network environment. When you have customers who use your products, and there's no personal interaction between customers, then what can you use that's as effective to bring customers back to use your product?<p>Features is perhaps the only thing, but it's not even remotely as effective in my opinion. And features can be a double-edged sword as they are quite often not really important to the customer.