Links are very important to achieve high rankings in Google but is it that simple? What if the sites linking to your site have been created solely for that purpose?
Having recently worked on a site where the client’s previous SEO company had bought up domains and created hundreds of mini-sites, I’ve seen firsthand it’s just not that simple. Each of these ‘mini sites’ had just 4-5 pages with keyword-crammed content and text links linking between each other and to the client’s site. Clearly this had been working; the site was achieving good listings for many of its keywords. The only problem was it didn’t last - these mini sites, along with the hundreds more spammy links to the site, were spotted by Google and the site dropped out of the top 300 for several of its key phrases.
The arduous task of ensuring all these links are removed is time-consuming and completely avoidable. Time and money spent trying to ‘cheat the system’ could have been spent using honest means of building relevant and trusted links.
One or two links from 'bad neighbourhoods' could easily have been acquired mistakenly, it’s impossible to be completely certain that a site linking to yours is completely spam free. In a case like this, though, where there’s hundreds of links, the site will inevitably be flagged by Google and penalised.