There's a reason Microsoft shut down the Microsoft Kin handset project so shortly after its launch in the US, it sold less than 10,000 phones.
Although word is circulating that the number was only 503 Kin handsets in total, Pocketnow.com has found out that there are 8810 active users for the Kin Facebook app, which is only available to Kin users.
It's unlikely that those unsold Kins sitting on a shelf in a warehouse would be able to activate themselves, which means that there is at least 8000 handsets in use around the US.
Of course, there is a strong possibility that there are even more handsets kicking around, based on the assumption that not everyone will sign up for the social networking site.
As Pocketnow.com says, if you read that 503 number anywhere else, then they just aren't doing their homework properly.
Let's hope Verizon announces the official numbers soon to end all the speculation. Either that or every Kin owner gets in touch so we can tally up the total.