One problem with friends is that it looks like nobody was using XML-RPC API methods for DW friends since the time when it was made 10 years ago so did not notice and report that it contains errors, e.g. group bit is not returned from server for groups so that groups cannot be used. But anyway, you can add people to subscription and access lists.
Also, sometimes the server adds a user to friends but returns reply without message that the user was really added. For me that happened 2 times. So Semagic does not know whether the user was added or not. In this case, the actual friends' state will be shown the next time when you update them from server.
Note that unlike LJ, DW does not return communities that you are a member of as friendofs. That means they will be shown in the list only if you are subscribed to them.
Download page: http://semagic.sourceforge.net