What is Google Dance?
If your SERP (Search Engine Result Pages) rank fluctuates, don't be alarmed. Everyone's rank fluctuates, and that is the nature of search engines. You may be happy to see your site rank highly on the most coveted keywords but don't expect it to last forever without constantly updating your site. Search engines are constantly tweaking their algorithms and new sites are constantly being added, so SERP ranking fluctuations are expected. Also, your competitors are updating their sites to achieve better rankings.