Overseas servers mean little to the US Government. I worked for the feds in several capacities, even thought of doing legal work for them at one time. As a former boss once told me, the feds go after whomever, whenever they want and it will be legal when they are done, regardless of whether or not they have any legal authority to do what they do. I have a brother in law that found that out very well...especially since he didn't have enough money to satisfy the federal spooks in making the case disappear before it was filed.
This is now the fed's attempt to convince the Supreme Court to allow it to collect emails from overseas servers in a criminal case. And trust me, the way the opinion will be written, because the feds will win either this case or one in the future, it will allow the government to collect EVERYTHING from an overseas server in a criminal case. Does this mean this site is going down anytime soon? Unknown. But if the site owners feel the heat, I am very, very sure that a fight to keep it all going will bankrupt them and most "free speech" groups aren't looking to take on this fight out of their own pockets.
Just Craigslist going down has now hurt my very legal side jobs of sensual photography and sensual, non therapeutic but better than most massages. Nothing wrong with being prepared for the worst...