I have been enjoying Andrew Chen's series on 'Fun with Web Metrics' so I appreciated Brier Dudley's love letter to iLike:
"Since May 25, iLike grew from 1 million to 6 million users. For comparison, RealNetworks' Rhapsody had 5.4 million unique visitors last month, according to comScore Media Metrix."
Whatever it is that 'Users' encapsulates, all time signups with a substantial proportion of effectively inactive accounts, or similar, 'Users' is different than 'Unique Visitors', which itself is not at all a good measure of a subscription-based, all-you-can-eat music service.
Let's see, additionally, Rhapsody owns the relationship with their users, Facebook owns the relationship with iLike users. Oh yeah - I almost forgot - pretty sure people pay actual real money every month for Rhapsody. My point here is how the comparison numbers lack, lets say, parallelism , as applied to web metrics.
Brier is totally on the mark in that iLike is totally killing it - and I know that this is largely due to 1 particularly brilliant, Seattle-based developer, and 1 particularly brilliant, Seattle-based designer - you know who you are!