Digital device and method of processing data therein

A digital device, comprising:

• a first receiving unit for receiving application data;
• a second receiving unit for receiving a signal including a request for a search service and search word data for the search service;
• a memory for storing search history data;
• a controller configured to:
• perform a first operation based on the search word data in response to the received search service request,
• control to display first search result data on a screen,
• if the displayed first search result data is not valid, add the received search word data to the search history data, and
• control to display second search result data on the screen by performing a second search based on the search word data included in the search history data after the search service;
• and
• a display unit displaying the application data, the first search result data and the second search result data,
• wherein if search data exists, of which text similarity to at least one of previously search data stored in the search history data is over a predetermined range, the controller determines the search word data as valid search word data, and
• wherein as a result of comparing search result data on the basis of the search data determined as valid with the search result data of the search word data stored in the search history data, if redundancy of the search result data is equal to or greater than a preset range, the controller saves the search word data having a large number of the search result data to the search history and deletes the rest of the search word data from the search history data.