This is something not often discussed but has serious impact to all-The Google Dance

During the month, Google sends out robots (spiders) to crawl the web and archive every website it finds. These archived websites will be presented in the next update of the Google index (database). The update process is initiated every 30 days or so, although on some occasions there have been more than 30 days between updates.




From my personal experience I've seen more impact on a 90 and 180 day and yearly cycle which has impacted me the most. So during that time whatever adjustments you want to make be it content,linking or others this would be the time to do it. Right now I'm expecting it any day though you can never be absolutely sure when it'll occur;-)