I'm involved in a start up that launched a few months ago. Although we're quickly becoming profitable without the need for google... a large part of the business is built around search engine traffic. A month after we launched we started to target some of our larger keywords. We used the service by Travis at SEO Supremacy. It's quite pricey ($400 a month for a private blog network subscription) but apparently it had good reviews. However 10 days after we signed up, our rankings dropped. We were getting around 150 people a day from search engines.... since using his service we're now lucky if we get 10. Turns out the private blog network is rented links on crappy russian blogs which clearly have a huge foot print. I've cancelled the subscription and asked for the links to be removed. But it's clear we've got a google penalty. Rankings have dropped so dramatically, we're not even rankings for seriously long tail keywords we were before. So now our entire traffic comes from social media. What would you do in this situation? Have you had a penalty before? What did you do? I personally have £8k invested in this project... so any advice is most welcome!!