One critical problem that could ruin your Quality Score – and your Google AdWords campaign.
It’s of critical importance that you maintain a high Quality Score for your AdWords campaign. It will make your campaign far more cost-effective.
However, if your website has malware or viruses on it, your QS will be penalised heavily by Google. And so will your SEO.
To make matters even worse, I believe you’ll be penalised if other websites (from other companies) on the same shared server, contain malware or viruses.
The major problem with this is that you won’t even know the problem exists. As far as I can tell, the only way round it, is to ensure you use a quality hosting company.
But, be warned, separating vendor’s marketing hype from reality is no mean feat.