The difference between a free Kshared account and a Premium one is night and day. Here is what a Premium Key unlocks:
Refusal.
Occasionally, forums post massive text files claiming to contain "thousands of working KshareD keys." These are almost never valid. If they do work, they are usually expired or revoked. Worse, these files are vectors for malware, keyloggers, and ransomware. Kshared Premium Key Free