One of my customer has an e-commerce site selling about 100 products. I read having a Blog is a good way to promote the products with Google. My question is: What's the best way to setup the Blog domain? If their domain is www.widgets.com it's better to setup the blog as http://blog.widgets.com (as a subdomain) or http://www.widgetsblogs.com (on a totally different site) or does it matter? Any advice would be appreciated.
I would setup the blog on my existing domain in a sub directory. This way you can keep adding lots of nice content to your blog and use it to interlink to your product web pages. I am going to assume that you would want to create product reviews, news or announcements for products that you are selling, so I would create categories in the blog related to the different groups of products you sell. For example, if you sold electronic products, create a category for this and place your reviews and news for your various electronic products in this and link out to the individual product page that you are reviewing for. I would use Wordpress for my blog. I would also consider using something like magpie to parse the blog and show 3-5 of the latest results on your home page. If you setup the blog on a subdomain or a new url, you will essentially be starting a new site and go through the usual processes that you would encounter with a new website. Hope that helps you.
I don't think you can lose either way. I agree that blogs can be a good thing. But, I might be inclined to go the sub-domain route. I would put a link or two on the client's site to the blog and then try and build some other links via blog directories, blogrolls, etc. to the new blog. Then have a day blogging about product news, industry news, etc.