There are different ways to approach constructing backlinks, one can blast it with thousands of completely irrelevant backlinks that have absolutely nothing to do with your niche and google will move you a little closer to the top of the list. But these types of backlinks would have been created using one of the many softwares that allow you to do this.
My personal belief is that Google rewards you less for these low quality backlinks, the sort that are not universal blog posts that could be shoved in place of any comment on a blog and count as a backlink.
If you were to take the time to comment on blog that has content relevant to you niche and contribute some relevant content to that site that links to your site, not only do you get a quality backlink to improve your SE ranking, you are likely to get visitors to your page via the link posted in your comment. An obviously spammy comment will be ignored or glanced over at best by everyone reading the responses.
You dont get a better ranking simply because there are more external links pointing to your site, the quality of those links counts a great deal. Its pretty easy to determine how to create quality links, just think about what would happen naturally. Which is why we use different anchortext and it pays to post different but relevant comments on multiple sites. This appears very natural to google and so you will be rewarded with a better page rank.
100 quality backlinks beats 1000 piece of shit backlinks everytime.