Customer Acquisition Cost, also known as CPA.
CANSPAM
The US Act of 2003 that regulates the sending of commercial email in the United States.
Churn
The percentage of customers who leave a service every month/year. Conversion Rate
The percentage of players who convert from free players to paying players. CPA
Cost Per Acquisition/Action. An online advertising model whereby an advertiser pays a publishing website a cash amount every time the website refers a consumer to the advertiser’s website and the consumer takes a specified action. It may include filling a form or registering, but the most common is making a cash payment. For example, EVE Online will pay $7 every time a referred user becomes a subscriber.It is also used by game developers and web publishers as a key metric to understand how much it costs them to acquire a customer from all of their marketing sources. CPC
Cost Per Click. An online advertising model whereby an advertiser pays a publishing website for each click on a link. Google’s AdSense program is based around CPC.
CPI
Cost per Install. An online advertising model, currently mostly confined to the iPhone, where developers/publishers pay a fee for the successful installation of an app.
CPM
Cost per Mille (or Thousand). The primary measure of advertising cost across all media (including television, radio, print and web). It measures that cost per thousand “views” of an advertisement. In an online context, it refers to the cost of a thousand impressions of a single banner.