• TweakUI can reduce but not eliminate
  • (alternatively, General > Focus > Prevent applications from stealing focus, that allows apps to steal focus, and then they won't blink at least)
  • note that you can't use Powertoys XP, you have to use an older version

• registry:
  • HKEY_CURRENT_USER\Control Panel\Desktop\ForegroundFlashCount — DOES NOT affect programs that use FlashWindow() instead of FlashWindowEx()
  • HKEY_CURRENT_USER\Control Panel\Desktop\ForegroundLockTimeout

• Win32 API
  • FlashWindow() — used to invert the status of the taskbar button. Doesn't include cycling functionality, you have to use FlashWindowEx() for that.
  • FlashWindowEx() / struct FLASHWINFO — used to start/stop automatic blinking cycles on any window (however, if FLASHW_TIMERNOFG has already been sent to a window, FLASHW_STOP apparently won't work? Also, FLASHW_STOP obviously doesn't stop FlashWindow() calls)
  • HSHELL_FLASH — an event that can be trapped via shell-hooking, it detects when ANY window (system-wide) requests a blink

individual applications that can be configured to withhold their own blinking

• Pidgin
  • Tools > Preferences > Conversations > Flash window when IMs are received    

• Lotus Notes / Sametime
  • File > Preferences > User Preferences > Instant Messaging > Options > Blink the message window