You can’t argue with the voice of Matt Cutts, Google’s head of search spam if he is offering Google ranking tips.
He was recently interviewed at SMX Advanced by Danny Sullivan. He gives a brief insight into web links versus social signals. Matt outlines at present that links are still a more powerful factor than social signals. Matt admits this may change in the future (he say’s 10 years) but not for now. Interestingly I wonder how Google+ factors into this as we have already seen links here becoming more influential as a ranking factor than across other social sites especially with local search. You can guarantee as they grow this social platform that Google+ will provide a higher ranking signal than other social sites.
There has been much debate around the power of social links espeically with the user base and size of many of the social channels and the amount of time that users spend on them. It becomes hard for Google to ignore this as a ranking factor. We imagine this will all change in the future but for now links and social signals should work hand in hand as part of your SEO strategy and don’t just focus on the social element.