Our site used to rank very well for some relatively competitive terms, until we were suddenly removed from SERPS for those keywords. This took place about 4.5 months ago.
The biggest suspect at this point in time is the fact that we purchased some paid links whose contexts were not all that related to our business. As a result there were a few periods where unnatural link growth was picked up..
Either way, what I would like to know is if anyone else out there has experienced a penalty like this. What is the best way to move forward and gain back decent organic rankings? What sorts of time periods are involved?