You can archive instant messages in the following ways:
Using the Portal Server Search-based Archive. This method captures instant messages and archives these messages in a Portal Server Search database. End users can query and retrieve archived messages using the Search page on the Portal Server desktop.
Using the Email Archive. When using this method, chat and conference participants receive emails containing the contents of the Instant Messaging sessions in which they participated. End users can use any email client to search and manage instant messages.
Using a Custom Archive. You can choose to use either the Instant Messaging archive providers, or create your own custom archive provider. Instant Messaging provides the APIs and SPIs that can be used to write custom archive providers. For more information on Instant Messaging APIs, see Appendix D, Instant Messaging APIs. Regardless of which type of archive provider you choose to use, you need to enable the archive provider in iim.conf.
You can configure Instant Messaging to use one or more archive methods at the same time.