One is malware, the other isn't. When I open their "Generate Bitcoin" page it won't run because I don't have Java, not JS, in my browser. If I did it would ask me for permission to run and if I said yes it wouldn't be persistent.
The Skype malware is classed as a malicious IRC-bot so unless it's very specialized it's safe to assume it includes other features as well, like DDoSing, searching and mass uploading of files ("wallet.dat"?), mass downloading and running of files (so the backdoor could be extended at any time), login form reporting and what have you.
The Skype malware is classed as a malicious IRC-bot so unless it's very specialized it's safe to assume it includes other features as well, like DDoSing, searching and mass uploading of files ("wallet.dat"?), mass downloading and running of files (so the backdoor could be extended at any time), login form reporting and what have you.