- The copyright holder who wants to squelch criticism and comment. Perhaps the most notorious example of this is the so-called Church of Sci3nt0l06y (given the litigious nature of that organization, it shouldn't surprise you that I am not giving it a searchable reference), which has tried to simultaneously claim certain texts as trade secrets and as copyrighted material. In the US, with our First Amendment tradition, it has been relatively difficult for critics to win lawsuits against the CoS, largely due to being outlawyered. That old saw about "fool for a client" comes to mind, particularly since so many of the critics have been pro se. Ironically, in a nation whose copyright law doesn't even include a fair-use provision, critics appear to have done substantially better against the CoS. The Wind Done Gone provides another example of this variety of copyright abuse.
- The copyright holder who wants to exploit a property for purposes other than copyright. One obvious example of this is Disney, with its repeated attempts to use copyright law and extend copyright law to protect that overgrown shirtless rat. The real problem here is not with direct copying itself, as almost nobody does that; instead, it is the parallel problem of protecting the value of the property against dilution (Air Pirates), as distinct from protecting the holder from criticism (as noted in the preceding point). As I discussed at length in the extended exploration of fan fiction, though, this really should not be treated as a copyright problem, but as a trademark problem. However, the procedural problems I described are even greater barriers when dealing with derivative works in differing media from the original, and the proof problems are more intractable even than "striking similarity"; thus the impetus to use (or misuse) copyright law.
So, then, what does that imply? Mostly, it implies to me that the differing remedies and evidentiary doctrines among types of intellectual property may be distorting doctrine, particularly in the US. That, however, shouldn't surprise anybody after Grokster.
n.b. I said "typically." I'm certain that there are examples that do not fall within these two categories. From what I've seen, though, many (and probably most) copyright abuse disputes fall directly within one of these two categories, and most of the remainder seem to resemble them rather closely in the course of litigation.