A Facebook ID is more commonly known as a profile badge. To create a profile badge scroll down to the bottom of your profile and click on the 'Add a badge to your site' link. This will take you to a new page where it will give a code for you to copy and paste on your website. You can also make other badges for your website. You can make like, photo and page badges and by clicking on these tabs to the left of your screen, you will be given another code which you copy and paste on website.
By going on to Facebook's developer's page, developers.facebook.com/docs/plugins/, you can add other useful plugins which will get your website noticed. You can add the following:
The Like Button: This plugin lets viewers of your website shares the content with their friends. When a viewer clicks the like button on your web page, the article from your site will be posted into their friend's news feed.
The Activity Feed: This shows the recent activities of your site. It will show which article has been liked and shared the most by Facebook users.
Recommendations: This will show similar articles to the users based on what they have shown an interest in.
The Like Box: This allows the website host to see how many people and friends have liked their page.
The Login Button: Lets users login and have their profile picture displayed on the website.
Registration: This allows a viewer to sign up to your website with their Facebook account.
Comments: This allows viewers to comment on your website.
Live Stream: This allows viewers to share activity and comments of your website in real time.
These will plugins will only work with views who have already signed up with facebook.