Until Google perfect the system, or develop better ways to start ranking and determine the relevancy of web pages to search queries, links are still the currency of search placements.
The more people are linking to your web pages (credible sources), the better your chances of getting higher ranking in search engines results pages. So, is out of question how important building back links is to search engine optimization of any website or blog.
The question is "How do you build backlinks"?.
