Legitimate link building is basically press and blogs relations (to maybe get links from journalists and bloggers, give them free stuff) and content marketing (

Legitimate link building is basically press and blogs relations (to maybe get links from journalists and bloggers, give them free stuff) and content marketing (invite a blogger to write for your blog, or write content on other blogs, and make links in both directions). It's not really manipulating the system, more like playing with a full understanding of the rules. Spamming every website out there with useless comments containing your URL is more shady business and can result in a ban.