The long tail keywords are ranking fine. The site is being indexed regularly. The main keyword is nowhere to be seen in the rankings despite good backlinks with good anchor text being built.
The main keyword has much higher competition than the others , so initially I thought fine, it'll just take a while. Overall it's not a high competition niche though, not many people target it.
The reason I now think it MAY be being penalized for the keyword is
(a) For the first two weeks the site may have been over-optimized for the main keyword. It was at about 11% keyword density. I took it back to about 4-5% a month ago.
(b) My site is not showing up at all in Google alerts for the main keyword. The long tail ones are showing up in Google alerts though. All kinds of crappy sites mentioning my main keyword in passing show up in Google alerts.
Am I being impatient and paranoid , is there something I've missed or could Google be penalizing me on that keyword for a time? If so how long would such a penalty last?