Read Alternative Tweet Embedding by Stefan Bohacek (fourtonfish.com)
When you embed Tweets on your website, Twitter asks you to include their JavaScript code that adds images, number of likes, and loads their styles.

But looking at the size of all the script files (yes, the one script tag loads multiple JavaScript files), does quite a bit more than that, including tracking your website’s users.

And it has pretty negative impact on your site’s performance as measured by Google PageSpeed.

Update: This seems to have disappeared and roughly remapped to