Drupal on Local Environment (Host) on Mac

HowTo: Create a local environment using MAMP
Read the above carefully
(More Info: http://www.lullabot.com/videocast/install_local_web_server_mac_osx)

Question: Do MAMP effect original OS X security after installation? Do we need to change default MySQL password? Or is it just a virtual host, not related our internet connection?

To Play with Drupal
1. Open MAMP, and Start Server
2. http://localhost:8888/yourdrupaldir/