What is Google Dance?

Google dance is a term used to describe the update of the Google search engine index. Earlier it was updated once a month. Due to this continuous updating, the search results were quite disturbed and often included in them backward links for the searches made. In 2003 Google changed its updating strategy in total and started doing it on continuous basis. Google dance is on all the time in continuation but there is still a need for complete updating of the index after small intervals. The search results have improved significantly and show very less effect due to the continuous updating of the search engine or the Google dance. Thanks to the Google dance that has enabled us to have access to the latest information available on the web. For example the links updated on a medical research done in continuation by a medical company and as the results come so are they announced and new links are provided and updated continuously. 
What is a key word?
Keyword tells us about the main idea behind a title. It can be a single word or even a phrase. It has a very key role in searching because it lets us about how to get the right results or may astray us from into the wrong ones. Before searching on any topic, one should brainstorm different combination of terms and synonyms to start moving in the right direction. Usually key words are used in searching for topics given in different kinds of assignments. A key word can be that mentioned in the assignment or closely resembles the one mentioned.