Abstract: In one embodiment, a method includes a computer server machine receiving a request from a first user to interact with a multimedia content. The computer server machine then associates the first user with a control group, wherein the control group comprises a first set of users interacting with the multimedia content. When the first user is associated with the control group, the computer server machine then applies a first content insertion model to the multimedia content and records a first set of metrics based on the interaction of the first user with the multimedia content.

Abstract: An online system acts as a centralized, trusted intermediary in managing subscription products that a user of the online system has subscribed to. For example, a user may subscribe to receive a product from a variety of different third party systems. The user of the online system provides payment information and authorization information to the online system which stores them in association with a user profile belonging to the user of the online system. When a payment is required for a subscription product, the online system retrieves the payment information and verifies that the online system is authorized to provide a payment. Once verified, the online system provides a payment on behalf of the user to the third party system in exchange for provision of the subscription product to the user.