Meaning of the short up and long downs

[Jamie]

My rankings have been bad for quite some time but I am in the process of making many “improvements”. Last night I noticed my rankings were very good to excellent for a wide range of keywords searched from South America. I had someone confirm the same ranking in the States and than this morning I notice these ranking disappeared.

My question is does this indicate a positive progression that my site may get the good rankings or is something triggering the rejection of the site being in the temporary position. I am not looking for specifics regarding my situation just the possible theory for the short up and the long down. If something is not right why would it be up even for a short time? This same situation happened about a month ago. Is there any assumptions one can make for this?

[mtheory]

Did you happen to change and update your index page between the good and bad rankings?

[Jamie]

No I have not made any changes during this time.