In 2001, a great strategy was to use multiple domains, each targeting a specific keyword target. In fact one company that we work with had #1-12 in the Google search for a particular geo term.
But the world has changed since then. Google has recognized the unfairness of multiple sites competing for the same keyword target.
Clearly it's unfair for one company to have more than one horse in the race. And getting caught being the owner of multiple sites monopolizing keyword searches can get your enterprise kicked out of the search results.
If you get caught.
But there are completely legitimate reasons to have multiple sites addressing some of the same keyword targets. Imagine a company that both wholesales and retails. Should they be FORCED to use only one site, even if 2 enables them to more accurately target their respective markets? We all know the answer. So how is it that some companies successfully manage to launch hundreds of sites, and some get penalized for launching 2?