With Facebook, you can include a Like Button on any page (or all pages) of your website. This enables visitors to your site to "Like" the page they are viewing and share it with their Facebook friends. Here's an example:
In addition, you can add a Facebook Like Box to your site. This displays the content from your Facebook Page live on your website. This is great for avoiding having to duplicate your data elsewhere. Here's how it could look:
With Twitter, you can include a Tweet Button on any page (or all pages) of your website. This enables visitors to "Tweet" the page their are viewing to share it with their followers on Twitter. Here's how it looks:
In addition, you can include your Twitter "widgets" on your site. In your Twitter account, you can obtain the code you need for this, and it's as simple as copying and pasting that into the website to get your Twitter Timeline displayed on the website, like this:Tweets by @BBCSport
Also, if you take a look at the News pages of the demo site, and view a news article, you will see that a user can "Like" that article on Facebook, "Tweet" it to Twitter followers, or "Recommend" it on Google +.