I used to get 5 spam messages in my orkut inbox a day-- all spam.

...My orkut inbox hasn't received anything new in the past four days

Open Communities are still being spammed heavily.

It's because orkut changed some default settings for notifications:

http://en.blog.orkut.com/2007/10/getting-too-many-emails-from-orkut.html

Nope, the messages i used to receive weren't Orkut notifications. They were purely from spammers on Orkut. I still haven't received anything new