Search vs social: no contest

The primary outcome of search engine marketing is that you are found by people who are looking to satisfy a need, but who don't know your brand or don't associate it with their problem. Search engine optimisation gets you listed high in the search results; search engine advertising puts your ad on the page for any search term you have bid on.

The primary outcomes of social media marketing are an amplified presence online, a more conversationally engaging brand, and greater word-of-mouth endorsement.

Two complementary approaches

As with search, there are two complementary approaches:

1. Optimising your social presence makes your brand a welcome member of relevant interest communities, allowing you to contribute to and influence conversations.

2. Targeted advertising in environments such as Facebook allows you economically to build brand awareness and, to a lesser extent, get response.
   

People googling for answers are more likely to become customers than people chatting on social networks; but Facebook and Twitter users are more likely to try new brands than those who avoid social networks.

Strong influence

Now that search engines are paying a lot of attention to what people are saying and doing socially, and are factoring clicks on Like buttons and +1 buttons into their algorithms, social engagement has a strong influence on SEO.

Simply put, search brings you hot leads. Social media makes your brand bigger and friendlier. Use both together, and you multiply your chances of marketing success, because a bigger, friendlier brand is much more likely to get great Google rankings.