Facebook Lexicon is like Google Trends – it lets you compare how frequently different words and phrases are written on Facebook over time. The popularity graphs are drawn using content posted on Facebook Walls, events and profiles.
Related: Find What’s Hot with Google Trends
Facebook Lexicon graphs are plotted relatively so you can easily figure out if topic X is more interesting than Y or Z among Facebook members. You may enter up to five terms, where each term can be a word or two-word phrase consisting of letters and numbers.
For instance, the graph below suggests that more people talk about Mumbai on Facebook than Delhi or Chennai. This is also a good indicator of Facebook’s relative popularity in different cities of the world.
The Facebook charts are done in AJAX/Flash so you can’t embed them in websites other than taking a screen capture as I have done for this story.