Rather than starting a blog, which is often bypassed entirely by users, you should take a more integrated approach to developing fresh content on your website and include it on product pages, where it will have the greatest impact to your revenue.
Attention affiliates: the keyword-rich domain name + perfect anchor text links formula is officially outdated. Here's how affiliates can update and fatten up their sites to accommodate Google's more recent changes and also anticipate future ones.
Google's Penguin update targeted sites with an unnatural link profile - those with a majority of their links coming from low quality sites along with overly-optimized anchor text. Here's how site owners can diagnose if they were hit and why.