[luser001]

Since the Sift guys are responding: from where do you get the raw data about fraudulent transactions? I'm assuming you have streams of fraudulent and valid transactions, otherwise you can't figure out what correlates with fraud.

[brandonb]

Our customers send examples of users that they've banned from their site or who have caused a credit card chargeback -- these are the $label events in our API and quickstart.

Those $label events let us do two really important things.

First, we can learn patterns that are unique to a particular site. Every site is a little different, so that has a big impact. Patterns that catch fraud accurately for an auction site may not work at all on a travel site.

Two, if a user gets banned from one site in our network, we can identify when they attack another site. That means as more sites join the network, the system gets more accurate for everybody.