I was running version 2.2.x of WP before upgrading today. I (like a dummy) forgot to backup my database, (got the folder/files) but not the DB. After upgrading I found that all my private data was now exposed to the world, since I was using Category visibility (the plugin) to hide my protected posts/categories. I had to impliment an emergency strategy with the only plugin I could find that actually worked with 2.3 which is Post Levels. I had to edit over 100 posts to set them to protected (after enabling maintenance mode). This was a major pain!!! I don't see any plans to port the Category Visibility plugin to support 2.3. But I desperately hope someone does or writes a new plugin to support the same type of security. I don't want to have to set options on each post, or do any per post configuration, being able to secure whole categories was wonderful. I tried other plugins that were supposed to do the same thing, but none worked with 2.3. So if anyone has any suggestions for plugins that work the same way as Category Visibility, I'd love to check them out. It would also be nice to see WP integrate this same type of security into its core code, so plugins for security of this type would not be needed.