Bad press got Microsoft to recently abandon plans for Smart Tags that turned words on web pages into hyperlinks that it or others
could control. However, another company's system to do this, called TopText, is live, growing in popularity, and has some site owners up in arms.  By Danny Sullivan.
 http://searchenginewatch.com/searchday/01/sd0823-toptext.html

Hello Friends..........

Smart tags are strings of text that have type information attached to them; when a text string that matches the criteria appears in a document, it is recognized and the user can perform actions appropriate for that type of string. For example, you could create a smart tag that recognizes stock symbols. When the user types an uppercase string of four letters, you could provide a list of stock-related actions, such as looking up a stock price on the Internet.

Thanks