> everything I read about maximising your web presence and impact told me that SMEs must integrate and embrace social media, especially Facebook
This is where he went wrong; signing up to Facebook because a book said a business needs a Facebook page to be successful online is the wrong approach. If you can't explain why you're making a Facebook page it probably isn't going to work, even if you have no knowledge of Facebook as a platform you should still have knowledge of human behaviour.
We're not a traditional business (we're an internet forum) and we have close to 100,000 likes at the moment, the value of having likes is seriously overstated, we get maybe ~300 click through's when we post an article and engagement is dropping more and more, in fact the same can be said of Twitter, we have ~6000 followers and get similar click through rates when we post something. They're not bad to have (Facebook page, Twitter account) but they aren't worth the time investment in most cases.
It seems now that liking a page on Facebook or following a twitter account are hollow gestures that don't really carry any weight in the future.