IMHO Social signals are currently overrated. That is not to say that I think social signals are worthless, just that they are overrated.
If you are serious about a website you should build up some social channels for that site. By developing a strong social marketing campaign you can actually develop real traffic that will convert. Plus it will make you less dependent on Google traffic with all of the traffic from those social sites. Not all social channels are a good match for every website so pick and choose wisely.
On the other hand if resources and time is limited then developing social campaigns might not be the best investment for your limited availability.