Optify (via Searchengine watch) carried out a study, which showed that websites at the top of Google get an average of 36.4% of clicks, those in second place 12.5% and those in third 9.5%.

That chimes in with an earlier Chitika study, showing that the no 1 spot on Google gets 34.35% of traffic.
Optify also says that being any further back than page two has no real business value for you at all.

Not surprisingly, as I work for a social media agency, I am a big believer in SEO + social working together.
For example, Comscore has shown that 50% of ‘social media exposed’ surfers search for product terms every day compared to 33% of non-exposed surfers.
In other words, SEO can help improve your rankings but social media can prompt them to try and find out more in the first place.

Then of course, the search engine giants themselves are constantly looking for ways to embrace so-called ‘social search.’

The San Francisco Chronicle has a good summary of how search engines are tapping into social.
As (MIcrosoft) Bing’s Paul Yiu says in the piece, “search up until recently has been a lonely experience.
We want to introduce people as an important part of search.”