Lexicon is a tool to follow language trends across Facebook. Specifically, Lexicon looks at the usage of words and phrases on profile, group and event Walls. For example, you can enter "love, hate" (without quotations) to compare the usage of these two words on Facebook Walls. You may enter up to five terms, where each term can be a word or two-word phrase consisting of letters and numbers.

Navigate to www.facebook.com/lexicon

The preview of the new Lexicon offers a variety of new tools to help you follow language trends across Facebook.

In this preview version we are giving you access to a few topics we hope you will find interesting. We will add additional functionality and index many more topics in the future.

Associations are terms that frequently show up in posts with the topic. For example, the terms "bat" and "mets" frequently occur in posts about "baseball."

The X axis displays the average gender of users who posted the association, weighted by the demographics of the Facebook population as a whole. An association at 0% would mean that only females mentioned the term alongside the topic. The Y axis displays the weighted average age of users who posted the association.

You can zoom in on a group of associations by clicking and dragging with the mouse. Press SHIFT to zoom out, or drag an area with no associations. You can use the slider at the bottom to explore the associations of the topic for different dates. Click individual associations on and off above the graph to see how those associations change over time. Roll over a bubble to see the exact number of mentions of the association alongside the topic in the given time window.

Window Length refers to the number of days before the given date that were aggregated to produce the data for that date. For example, a window length of 14 for September 19th includes data from all days between September 6th and September 19th.

Sentiment displays the percentage of subjective mentions of a topic that are positive vs. negative. The score is equal to the number of positive sentiments divided by the number of positive and negative sentiments.

Sentiment is computed automatically using a system that identifies positive and negative posts about topics. For example, the post "I love Facebook" would be counted as a positive sentiment. The post "I use Facebook" would be considered a neutral sentiment and not included in the score.

Pulse shows keywords that often show up in the Profiles of users who mention a topic. It is drawn from the favorite Interests, Movies, TV Shows, Books, and Music of those users. You can use the drop-down menu to change the category.

These interests are ranked by a combination of the total number of posters who list the interest in their Profile and by how closely associated the interest is with those posters. A close association means that the interest is more likely to show up in the Profiles of users who are talking about the topic than the average Facebook user.

Maps shows where people are talking about the topic. The darker the region, the more people in that region mentioned the topic. In the Show as Percentage view, the color indicates the percentage of all posters in that region that mentioned the term in the given time period.

You can compare two topics with Maps. The score for each region is the log ratio of the two topics. In the normal view, the color indicates which of the two topics has greater volume in each region. In the Relative Comparison view, regions with a stronger relative association to each topic are highlighted.

We will open up additional languages, countries and demographics in the future. Stay tuned!

Lexicon shows the number of users that posted each term per day on a profile, event or group Wall. It does not count repeated terms by the same user on the same day. This is to account for the seasonality of Wall posting in general; for example, there are fewer overall posts in the month of December. The text of each Wall post is also "cleaned" before it gets counted. For example, every word is converted to lower-case, and apostrophes are removed (so "You’ll" turns into "youll").

A term will only be displayed if there have been sufficient mentions of the term to display results. If a term doesn’t show up in the graph, or if there is a gap, it doesn’t mean that no one mentioned it; it means that not enough people mentioned that term for it to exceed the threshold.

Lexicon data is completely anonymous and simply looks at how popular words are on Facebook’s public and semi-public forums. All personally identifiable information is removed before the Wall posts are aggregated. Lexicon does not look at any private data, such as data from messages, Chat, invitations, or searches.

Lexicon displays as many data points as possible that fit on the graph. When you remove one of the search terms by un-checking the box above the graph, or move the slider to zoom in on a particular time range, we redraw the graph to make the results easier to read. This may cause the data points to change their relative position on the graph.

You can click/drag either the left or right button on the slider to increase or decrease the amount of time you want to view on your graph.

The count for each day covers a period of 24 hours starting from midnight Pacific time. In Lexicon, the dates and times are displayed in your local time. So for example, data for the day that started at midnight on Monday, April 7th PDT will show up as "3AM Monday, April 7th" for someone in New York, or "9PM Sunday, April 6th" for someone in Hawaii.

Lexicon counts words and phrases that are composed of numbers and letters in the English alphabet. If a term (after it has been "cleaned") consists of numbers and letters in the English alphabet, and exceeds the count threshold, then it will be included, regardless of the language.

Absolutely!