It says that the easiest way to create a bit of code to embed a tweet is to click on the Embed link in the tweet...
I can't see, when I look at a tweet's individual page, any mention of an embed link as they show in the example so I wonder what I'd have to do to make it appear..
At the bottom of the page there are two bits of code and this is one of them - it might embed a tweet, it might not, let's see
Search API will now always return "real" Twitter user IDs. The with_twitter_user_id parameter is no longer necessary. An era has ended. ^TS
— Twitter API (@twitterapi) November7, 2011