searchable archive of every tweet ever published. It is free and open to the public. So even if you are not a Twitter user, you may still want to see if anyone has referenced your report or journal article. Or you may decide it's time to clean house on some of those old tweets! This Guardian article tells you how.
An advanced search option is available if you need help narrowing down your search results.
For a breakdown of the technical aspects involved, read this blog post.