If I am selling bubble gum and other products on my website, and I own bubblegum.com, can I buy bluewidgetdohickies.com and redirect to bubblegum.com in order to get more hits on the widgets and dohickies product searches? Also, even though the bluewidgetdohickie name is available, should I buy it as blue-widget-dohickies.com? And then I submit that name to the search engines?
bluewidgetdohickies.com won't do you any good unless you promote it. Why not just promote the bubble gum site?
I wouldn't bother with bluewidgetdohickies.com unless you have the time and resources to make bluewidgetdohickies.com a successful site all in itself. For example, maybe there is a niche your main site has trouble promoting. But don't buy the domain if the sole purpose is to promote bubblegum.com.
Unless each domain can "stand alone" however by virtue of uniqiue content and linking patterns in and out, dont expect them to last long in google at least. They may have some type-in (non Search engine) advantages but not really if the domain names are this long.
As I mentioned in an earlier message the other day, my main site sells 10 categories of products. Only the category of which we own the domain name (bubblegum.com) is high in the SE results. The other products are not getting traffic. If I own widgetblue.com then maybe we will get more hits on blue widgets.