Google +1 Button introduced in March have been made available to the web world on June 1. Now the developers can use the +1 Button on their websites, blogs as well as it can be used on the Facebook Pages (Example VanityPlaza).

"Search results can be more helpful, and more personal, when recommendations from the people you trust are there to guide your way. The +1 button can help publishers, too. As potential visitors see recommendations from their friends and contacts beneath your Google search results, you could see more, and better qualified, traffic coming from Google." Says Evan Gilbert (Software Engineer, +1 Button).

Get started with the Google +1 Button for the introduction have a look here

On the other hand its the Facebook Like Button

"Like is a way to give positive feedback or to connect with things you care about on Facebook. You can like content that your friends post to give them feedback or like a Page that you want to connect with on Facebook. You can also connect to content and Pages through social plugins or advertisements on and off Facebook." Says Facebook