[Paul Whitener Jr.]

1. spam messages!

I really like this plugin for managing spam registrations and comments:

https://wordpress.org/extend/plugins/stop-spammer-registrations-plugin/

Signing up for an Akismet key will also help with spam comments, as would requiring someone to create an account and login before doing so (in Settings: Discussion).

2. am using bp on my 3rd blog. somehow users can not delete their’s account.

You can enable this in: Settings: BuddyPress: Settings (tab): Allow registered members to delete their own accounts

[Paul Whitener Jr.]

This issue was resolved by ensuring that my WPMU wp-config and bbPress bb-config settings matched those described here:

https://bbpress.org/forums/topic/login-integration-issues-bbpress-and-wordpress-mu#post-62274