I think the title speak by itself, it seems Bitcoin is becoming harder and harder to use for anonymous activities like DarkNetMarkets.
It is probably opening a road for altcoins that will allow a higher level of anonymity and security that Bitcoin can't provide.
Article :
Academic Paper :
Did you read the paper? It requires users not be using TOR. The first step they go through is basically forcing Bitcoin nodes to not accept TOR connections temporarily.
A smart user simply wouldn't exchange bitcoin then, they count on users switching to non-TOR connections.
Use TOR and this entire scheme fails.