If your application requires authentication, you use the following terminology FriendFeed nickname or email and Remote key in your login form. Your login form should contain a link to http://friendfeed.com/remotekey for users who have not memorized their key. It should open in a new window using target="_blank" so that the remote key page does not interrupt your application's flow.
We suggest the following authentication UI if it is consistent with the user experience of your application:

An HTML template for remote login is available if your application is a web application.
For more information about authentication and the functionality available in the FriendFeed API, check out the FriendFeed API documentation.
You are free to use FriendFeed logos in your application. However, it should be immediately obvious to your users that your application is not formally affiliated with FriendFeed. Likewise, every logo should link to http://friendfeed.com/.
The following logo sizes are available:
The FriendFeed API is new, so we expect it to change over time. We will do our best to maintain backwards compatibility between releases, but incompatible changes may be required in the future, particularly in the first few months of the API's existence.
The API imposes rate limits for each IP address and each user account. For example, if you upload a large number of images with the API, your API requests will eventually be rejected with HTTP error code 403. We may adjust these rate limits over time to maintain the quality of service on friendfeed.com or to curtail abuse.
All of the actions your application takes on behalf of FriendFeed users should be obvious and transparent to the user. If we receive complaints about an application abusing the API by, e.g., publishing entries excessively or reading data secretly, we will disable the application and IP addresses associated with the application.
The FriendFeed API is provided under the FriendFeed Terms of Service. We reserve the right to disable access to the API at any time; please use the API respectfully.