Importing jams from the internet has some intrinsect risk; worse case scenario an attacker could erase every jam. Or worse, poison your editor so that every jam you create has a hidden virus virus.
As long as we trust the people we import projects from, we are safe. Aren't we?
Well it's not that simple. A person; in theory; can put arbitrary code on a Web Jam.
And if you write a jam that contains something like this:
code