How would I go about implementing share buttons automatically?

There are many sites that auto-generates pages with like buttons, tweet buttons, and stumbleupon buttons. My question is, how? I'm kind of interested in the logic behind it, but if there's a code out there that makes it easy开发者_StackOverflow社区 to do, I'd gladly hear it. I do not plan for my site to be dynamic, but this automatic way of inserting share buttons can be a great lazy way to add share buttons to a page.

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There is a great service called AddThis.

It also includes analytics, and works using JavaScript rather than PHP.

Search Google for tons more similar services.