Link building is an essential practice for SEO. Links are a key metric Google and other notable search engines use to determine a website's overall quality, relevancy and popularity.
Google is constantly dropping out poor link profiles, and the evidence of this was with the Penguin update released earlier in 2012. This is where it gets more complex because while websites need more links, they very much need to be getting the right type of links for short term and long term success.
There are many information and news regarding what the Penguin Update was, and one of the main aim of the Penguin was to improve the results by enforcing the guidelines. Google marked down good quality content websites in their algorithm if they felt they had manipulative link profiles.
Unfortunately this was quite difficult to take for many companies who had invested their money in building links for their business websites. The accepted practice in link building was to have the exact anchor text backlink for the keyword the website was going to rank for.
Having hundreds, or even thousands of links with the same anchor text simply looks manipulative and this is one of the factor the Penguin looked at. So while this strategy of link building was widely accepted in the SEO community, it ultimately was not long term secure.
It has been quite a long time since small business owners and SEO professionals are too interested in building their links and focusin on the numbers more than too much. The term can come in mond in this situation because SEO should be focusing on quality links to help build the site's domain authority rather than running around the internet to build links from blogs, forums and social bookmarking websites.
Websites are build to survive the competition on the World Wide Web. As the internet grew larger, competition is getting tighter when hundreds of websites are activated each day. Webmasters and business owners use numerous methods to increase their websites' credibility on the internet by pushing the best out of their marketing efforts. Building an authority on a domain name will effectively make sites have links that will build and work on their own.
Since the Penguin, it is more about the domain authority and PageRank a link passes, not the anchor text used. Exact anchor text still has a place in link building, but only a small percentage of your overall link profile should be using it.