Well, this is not a trick or a hack but a new ‘silent’ update by orkut. Even if you are not logged into orkut but want to check out any new activity on your favorite orkut community then this feature will be useful for you. You just need to navigate to the community url
Due to security settings by the community owners, you can not view the content in some communities if you are logged out of orkut. For example, check my community link i gave above. If you adjust the settings like what this community owner did, you can navigate to all topic replies in this community without the need of logging in to orkut. You cannot participate in the conversion though.
This will be really helpful for those who are browsing from a cafe and can now check the activity in their communities without fear of logging into an unknown computer.