The integration of social media into your online channels does not limit to simply including social media widgets on your website. Although, that is a good start.
True integration of social media occurs when you utilise the principle of social online interaction in the way that serves the purpose beyond just sharing your content for others to see.
It is also important that you think of your website, Facebook, Google+ or Twitter not in isolation, as separate platforms, but as integrated media which only when combined together will really maximise your audience reach and ultimately conversion. Sometimes we forget that in the good old World Wide Web everything is interlinked.
If you have a website and are present on Facebook and/or other social media platform then each one of those online channels should promote the other.