Is link building still a major factor for good ranking in SERP’s of Google?
Backlinks still form the #1 contributing factor in getting a page to rank in Google.
- High Quality back-links are better than high quantity back-links
- Freely-given links are better than procured back-links (procure can mean artificially gained in any manner, not just bought)
- Page Rank still matters in terms of the currency of back-links
So then it comes down to what you define as "link building"? If you mean providing rich, orginal content that other's find worth linking to - then yes. If you mean dropping links in forums, comments, directories etc - then no.
The biggest reason modern era search algos all love backlinks is because a trusted, organic link is still the hardest form of citation to acquire on the web...especially, at scale. (source)
More ranking factors are broken down here: http://www.seomoz.org/article/search-ranking-factors (this is accumulated opinion, not fact).
Yes, it matters the most. What's changed are some of the nuances of the linking.
There is some evidence that suggests that recent updates do more than simply count the anchor text from an external link but also more strongly consider the semantic content matching threshold between the pages. So, if you have a blog comment or forum profile that doesn't match semantically (too low) or is keyword stuffed (too high) it won't count as much as a more natural contextual page/link combo (just right).
Another nuance is thats been introduced is a more refined level of scoring the authority of links. This tends to be in flux and, therefore, is hard to nail down. But things like active age and authority of externally linking sites remain at the top of the list.
As Mike noted, SEO is mostly accumulated opinion and sometimes those who're accumulating opinions are trying to sell their SEO services or get SEO seminar speaking engagements so bear that in mind.
Yes Link building still plays an important role to rank your site in Google. As long as you acquire quality instead of spammy links and apply an advance link strategies. You can read this source for more info.