I would like to share a recent experience that we faced with a client of ours, a call on a nice productive evening informed us that their rankings had disappeared, disappeared??? I mean unbelievable, since there were multiple teams working on the site and overlooking each others work - so any mistakes would have been caught. So we did our ground work and it did turn out that the rankings had indeed disappeared. After a round of some shouting, arguments and a little panic in the department, some searches were made online - google panda update - google algorithm update - site penalized etc. etc. i mean when you are on top of these things and still stuff happens, what do you do? obviously you revert back to what Google "God" has to say about these things.
Articles and forums were scanned - things about google dance and proxy searching in other datacenters were highlighted - but then the most unexpected thing happened - the rankings came back but were case sensitive - case sensitive????? isnt google search "Case Insensitive"...??? and then the rankings went into oblivion again - then came back and then went again??? After about 3 days of Google god playing torture with most of us at the online marketing department - the rankings came back and (fingers crossed) have been there for 3 days now, so we are all hopeful that the rankings are here to stay for the good.
So, we have finally termed this as a twisted case of google dance and documented it so if it does happen again - we loose less sleep and can move ahead.
Just FYI - if this does happen with anyone, please do not get into aggressive link building from the very onset of this, resume your normal activities else google may mark your site as a spam website.
Hoping others who have had similar experiences would share them with us, so we can also work on the concept of crowd sourcing and improve our skillsets.