It is rarely ever legal to share license keys even with your own immediate family members for any software or online service. The only keys that are "legal" to share are those for trial versions etc that are licensed for free distribution anyway. Sharing keys for software/online services such as Ultra MP3 (including the mobile version) is the equivalent of pirating, because you obtained such information without paying for it - which is the whole point of having license keys: to be able to use such software or online service and prove that you did purchase it.
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