My personal opinion: although I can envision the risk of a drift towards a stricter policing regime, the immediate reason of such lawsuits is well grounded on a rather prosaic level: money (or should I say the lack of...).
The old media tycoons are suffering significant revenue losses both from the advertising and the copyright royalties.
Direct sales of hard copies of copyrighted materials (software, movies and music of course) are suffering a perennial downturn. Although the majors are cutting their losses, through on-line distribution, the hostilities against file-sharing have not ceased at all.
On the other hand, the market for on-line advertising has become more and more relevant (Google is constantly increasing its ads revenues), in spite of the traditional advertisement on radio, television and newspapers, which is progressively loosing its share. In fact, the money spent by advertisers tends to be steady and the overall advertising market is not really growing. Thus, it is the same old pie, except that slices are shared differently.
However, both in the Mediaset v. Youtube and in the Pirate Bay case, the problem is not limited to a friction among opposing commercial interests. The situation is way more complicated because Italy and its government interests are complicated.
In Mediaset, it is enough to say that the plaintiff is -somehow- the Italian prime minister, Berlusconi. There is no need to explain his interest in communication and public opinion. Moreover, in Italy some of Berlusconi's main opponents are leveraging the Internet and Youtube to drive their political activities.
As The Pirate Bay is concerned, there are too many things to say.
Access to the Pirate Bay web site has been blocked from Italy and do you know where is the URL re-directing? To a website hosted in England and owned by Pro-Music, namely the majors' association who is "behind" the lawsuits.
This is not quite all: when accessing the Pirate Bay site from Italy, Pro-Music is able to collect information about every user and his cookies-- using such cookies it is possible to access the user's profile in the Pirate Bay database, perhaps giving a look to what files such user recently downloaded, uploaded or searched.
This is enough evidence to bring a strong case in court, of course if we assume it was acquired lawfully.
I found a video-demonstration of how it is possible to hack Th Pirate Bay users' identity. Click here!
The Italian URL www.thepiratebay.org is not re-directing any more to the Pro-Music web site. The reverse DNS now says "localhost"...
Meanwhile some Italian associations brought the issue before the Privacy Authority. We'll hear about the Pirate Bay again...
WHO IS HIDING IN THE BAY?