[edited by: King_Fisher at 5:23 pm (utc) on Aug. 26, 2007]
For example, if you are Coca ColaCorp, and you own cocacola.com, you have a pretty good defense against coca-cola.com.
But if You are Jim Spiggins from Anytown, and you own bakedbeans.com, you have no say over baked-beans.com
If 'widget' is yours (ie you own the trademark), then it's worth fighting for it - but if it's generic-generic.com, then, sadly, no.
Remember Quadrille's Oft-Quoted Ninth Law - "If you own a quality domain name, then use it - or you may find the quality was an illusion"
In general, using a strong name is the best defense against having the name undermined by another site; but trademark ownership trumps almost very hand.
Quadrille's Oft-Quoted 15th law
Always buy domain.com, if only to permanently redirect it to domain.somethingelse
There are very few honest guarantees in this business (plenty of dishonest ones) - but losing out to the .com ranks up there with the best of them: it's a dead cert.
Dot coms have many structural advantages; in browsers, in search and in visitors minds. Few people looking for a dot com accidentally get the dot net - but many who wanted the .net will end up on the .com. In most cases, using the .com is also preferable, the main exceptions being non-US local sites, and some non-English sites.
... After this discussion, I'll need to think seriously about:
"Always consider buying domains with similar names to yours ... before someone else does"
That's probably the basis of Quadrille's Oft-Quoted 27th law, once I've got the final wording right ;)
Of course if "blue widgets" was just an example and you do have a unique name and trademark, you've probably got a fighting chance.
Marshall