It is true that you can receive huge amount of targeted traffic for Free from Social Networks, this is possible only if you can spend lot of time and effort in each of the social network.

It is important to build reputation on your profile in these sites to drive targeted traffic.

If your business receives good amount of traffic from other social network sites then you must be aware that traffic flow is not consistent over a period of time. There will be spikes in traffic graph from social network sites