As is customary, Scoble has gathered several links to the interesting opinions on Grokster case. In the following post he gives us his view:

I was wondering to myself today: "Is Bram Cohen packing his bags?" I can just imagine the lawyers are working overtime to write up lawsuits against BitTorrent that he developed. Yes, even if he could prove that he wrote it for legitimate file sharing (for instance, for putting your own podcasts up and sharing those with your friends -- Adam Curry on Saturday says he's going to support using BitTorrent to distribute his podcasts since each podcast he puts up is eating up hundreds of dollars of bandwidth fees and his site was unreachable earlier this morning) I imagine that Bram Cohen will get taken to court to prove that. Lawyers are expensive. Defending a court case like that -- even if you win -- will cost millions.

Don't worry Robert - this decision has nothing to do with BitTorrent, and I'll tell you exactly why. First, let's see what did Supreme Court exactly say:

We hold that one who distributes a device with the object of promoting its use to infringe copyright, as shown by clear expression or other affirmative steps taken to foster infringement, is liable for the resulting acts of infringement by third parties.

First of all, BitTorrent is not a network. If you want to share something using BitTorrent you need to do the following:

1. Decide what to share (one file or a hierarchy of folders), from now on referred to as data.
2. Gather all metadata about the data you will share. This metadata is kept in a file with the extension "torrent" aka torrent file. Whoever wants to download that data needs to get the metadata first (in other words, torrent file). The torrent file can be downloaded from a Web page, sent by email, FTP or any other means.
3. The metadata file is then fed to BitTorrent application. There are dozens of implementations (including my own, soon to be published) and they all (to my knowledge) interoperate even though they run on multitude of operating systems.
4. The crucial part of the metadata is server address/URL (server is also called tracker). The only use of the tracker is to give each BitTorrent application information on which other users (BitTorrent applications that is) are interested in downloading the same data. Get this - tracker is usually a simple, single PHP or ASP.NET page running on a plain standard Web server.
5. From that point on, BitTorrent apps communicate between themselves and share pieces of the data until the download is completed.
   

What this all means is that there is no such thing as BitTorrent "network" - trackers for various files (data) are scattered around the world and each tracker, well, tracks a (usually) small number of files. There is no single individual or company that stands behind all (or most) of these servers. Without servers, BitTorrent apps cannot find^* other BitTorrent apps and thus can't share anything. Therefore, BitTorrent applications cannot themselves do anything to "promote its use to infringe copyright". The servers that index copyrighted material and provide both torrent files and trackers are the ones the above court ruling applies to. One of the best known ones (recently shut down exactly for the reasons stated above) was suprnova.org.

That said, the Supreme Court decision is vague enough to induce further debate and complicate the decisions of the lower courts and personally, I don't like it at all.

^*I am aware that the latest beta of official BitTorrent client does not require servers to find data, but it's a topic for another post.