Google is rolling out new user interface for Keywords feature in Webmaster Central, and “will be updating data daily, providing details on how often we found a specific keyword, displaying a handful of URLs that contain specific keyword. Significance column compares frequency of a keyword to frequency of most popular keyword on your site. When you click a keyword to view more details, you’ll get a list of up to 10 URLs which contain that keyword.” “This’ll be useful when you re-implement your site on a new technology framework, or need to identify which URLs may’ve been hacked. For e.g., if your site appear in search results for unrelated terms ("Viagra" or "casino" etc.), you can use this feature to find those keywords and identify pages that contain them. This’ll enable you to eliminate any hacked content quickly,” GWC blog.