I see many products that create wallets with new addresses. But what is to stop some of those addresses from being the same? Could an address that matches one already in service be created?
The chance for an address collision to happen is nonzero but extremely small, since there are a total of 2
256 private keys and 2
160 valid bitcoin addresses.
https://bitcointalk.org/index.php?topic=104461.0;all could help you understand it better how tiny the chance is.