If you use the Jabber Service with the Adium client, and log in at multiple locations, Adium will log the second instance of the user in and out.
The solution is to rename the Resource for the Jabber Client. Each instance of the program will require a new Resource name, which is stored locally on the machine.
- Go to Adium > Preferences.
- Under Accounts, select the account and click Edit.
- Under Options, change the Resource name to anything that is not the resource name of the other machine. The default resource name is "Adium".
- Click OK.
Note that this issue only appears with Jabber. Gaim will not exhibit this problem.