A few months ago when I started to experiment with bitcoin I came across The Silkroad (only accessible via Tor)
For those who do not know what Tor is and who do not want to waste their time installing and checking what is there - you can read this and this comprehensive paper regarding The Silkroad.
In the paper, researchers stated that as much as USD 1.9 million/month is circulated on The Silkroad and most of this money are generated by drug products.
My question is - how it is possible that this site (aside from being completely illegal) was not closed? At one point in time it was quite notorious and there was even a hearing in the senate, but nothing came of it.
What makes onion domains so special that even knowing it carries large amounts of narcotics-related transactions it is still impossible to close it.