This might not be new but it's certainly worthy. I use this completely legit method to get many do-follow backlinks from .edu and .gov websites. The method I am talking about is developing Open Source software and making it available for free download. You can insert a small backlink say "Powerd by YOURSITE" to your website. I agree most webmasters just remove the link but I have seen these .gov and .edu sites are maintained by not so mean webmasters and they do keep the backlink in place. So go ahead and choose a popular CMS, find a commercial product which is selling hot. Develop an open source alternative and upload it in popular download sites. Within weeks you will see quality backlinks Hope this helps someone !