The Metrics Recorder plugin records an array of site usage and resource access metrics data, to help analyze site or collection usage. It does not display or otherwise provide any visible interface for the data -- the Metrics Reporter plugin is required for that purpose.
The plugin records two types of information, event data and sampled data. Examples of event data recorded include user logins, new account registrations, keyword or fielded searches, full record views, and OAI-PMH harvest requests. Examples of sampled data recorded include the current number of users, current number of resources, and the current number of users who have rated resources.
While the primary intent is for Metrics Recorder to be used in conjunction with the Metrics Reporter plugin, the recorded data could also be mined via custom code or a new plugin for a wide variety of purposes. The MetricsRecorder object already includes some methods for this purpose, however if there is data you would like to retrieve that is not currently accessible via a method, please consider contacting the Internet Scout development team to have a new method added, rather than pulling data directly from the database.