Linden Lab has found and is in the process of fixing Calling Card (CC) bugs in Second Life™. Recent work has found some CC problems affecting performance. One fix LL will likely put in is a feature to remove duplicate CC’s.
Having a CC triggers lookups at login and other times during a secession. With some people having 50k calling cards that puts a heavy load on viewer and server. An older but common tip for improving viewer performance is deleting all your Calling Cards. If you are not using them, there is no point having your viewer doing the work to update CC status for those avatars.
The fixes will start to appear in the next round of maintenance fixes. 2 to 4 weeks.
The plan is if a CC is that of a friend then they the card gets a status update at login. As it is now that happens for all cards. In the future if the person the CC is for is NOT a friend then there will be no status look up for that avatar. This should remove lots of work for the viewer, server, and communication channel.
There is apparently a problem with CC’s in note cards. Oz was not aware of the problems. They will try to get those in this round of fixes. But, they will need good information on the problems.
If you are wondering what people use Calling Cards for, check the Firestorm classes schedule. They have a class on how to use CC’s and the enhanced management system for CC’s built into the FS Viewer.