Hi, kien

You are right to be concerned by this limitation. Yahoo has indeed set up some protections to avoid ddos & spammers. Problem is: there is no documentation of what is allowed and what is not.

So i've tried to find them out and my conclusion is that there is no exact answer. Adding one user every 5 seconds can make your account banned (error 999) for several hours after 7-8 contacts added.
I did several tests and i had the feeling that adding non-existing yahoo users was getting banned even faster.

If you find any information, no matter how, please let me know here! I'm interested by this (and I'm not the only one)
(http://developer.yahoo.net/forum/index.php?showtopic=8071)

Cheers,
Thomas

I hoped some yahoo technican here, and he will reply soon :)I search in Google and Yahoo search but very few document about this SDK.

It would be nice to hear back about this.  It looks like I need to wait several hours after I add six contacts.  I've tried slowly adding contacts, but can't seem to get more than 8-12 in a day.  This is not good.  I'm willing to follow any additional protocol.

Thanks