Imagine, if you will, that I have the domain widgets.com. Now, I could have the usual widget.com or www.widgets.com, or I could use sub-domains to make it more interesting. For example: buy.widgets.com, get.widgets.com or blue.widgets.com. (Another example is del.icio.us). The reason I ask is because I'm working on a new website, and I'm wondering which URL I should use in my link building campaign. I only plan to have one sub-domain, and use it all of the time. The opportunity of having an extra keyword in my URL is quite attractive. Is this a good idea? Is there a possibility of a penalty or something if I don't use the traditional widgets.com or www.widgets.com? TIA, Cryo.
I would go for more keywords in the domain, it’s a plus to your serps and having 2 words in a sub domain is perfectly fine from the usability point of view. However keep in mind the number of levels your content will be from the root directory that could potential cause you a small seo disadvantage.
If the content is related with your main site, you'd better use sub folders. If it's not related and similar, you'd better use sub domain.
The point I'm making is that the sub-domain would become the main site. I.e. buy.widgets.com would be the main site, and any visitors to the main domain would be redirected to this sub-domain. Just like del.icio.us. Try going to icio.us or www.icio.us and all you'll get is a 404.