Links are the most important SEO factor.
Though, not all links will do you good.
Google’s Page Rank algorithm was developed back in 1996 and meant to rank web pages based on recommendations from other websites (backlinks). Google’s Webmaster Guidelines clearly described what sites needed to do to earn links. But many webmasters chose to take the shortcut and instead of creating high quality content, which will earn links organically, they started link spam activities such as link buying, participation in link schemes, hidden text, doorway pages, etc.
But it all ended with the Google’s Penguin Algorithm Update. Sites that were taking part in link spam suffered badly, lost rankings and some of them went out of business. The moral: Link building has to be done the right way or you can harm your site instead of helping it.
How to Do Link Building Right?
Think about this: what you need to do to make other webmasters want to link to your website? Here are some of the possible answers to this question: