I produced a video once for a baseball card shop in SE Michigan. The guy who ran it wanted a CD-ROM (this was 1999) to give out at a trade show of some sort, and his card shop was one of a handful of places in the States that could (forgive me if I'm off, I don't recall exactly...) validate the authenticity of a certain sub-set of trading cards. The name of the card place had the word "monster" in it as well; as also his logo was a green monster.
He told me of this incident he had with monster.com (whose logo was a green monster). They sent him a similar cease-and-desist letter, probably figuring that a letter from some big bad lawyers'd scare the heck out what they probably presumed was a small shop owner. It turns out, though, that this guy is insanely wealthy - he had something to do with the development of the plastic assembly that houses air bags, *if I recall correctly, which I may well not*. Anyhow, he sends this hilariously antagonistic letter back to monster.com inviting them to pursue legal action, which they did not.
Why not? He explained to me what his army of lawyers explained to him: These big corporations with trademarks *must* demonstrate periodic efforts to defend their trademark; for two main reasons: 1) the lawyers in charge of this stuff must demonstrate their worth to their masters, and 2) in some twisted legal way, if efforts are not apparent toward the active and constant and vigilant defense of a trademark, it is in jeopardy of losing its standing as a trademark! Apparently, then, these weasel-lawyers make a habit out of picking on mom-and-pop places who've neither the inclination nor the resources to wage legal battle so they can hang some heads on a stick and show it to their bosses each quarter.