Amy Green

Login errors in WordPress can be used by hackers to guess whether they entered wrong username or password.
This is a lightweight plugin that will hide those login errors and make your WordPress login more secure.
Features: 
* No annoying settings to deal with. 
* Install and automatically hide login errors. 
* Lightweight with only a few lines of code.

Hide Login Errors

Login errors in WordPress can be used by hackers to guess whether they entered wrong username or password.

Ismail

Does the same functionality as BuddyPress, emailing users who get mentioned in a bbPress topic or reply. The aim of this plugin is when to enable that feature when no BuddyPress is there. 
To do: – warn user about bbPress/BuddyPress presence

bbPress Mentions Email Notifications

Adds the @mentions to bbpress - really useful

Great plugin

Email bbPress topic/reply mentioned users, set custom email and some basic settings

Hide Login Errors vs bbPress Mentions Email Notifications