1. Modify Hosts File

Step 1:
To edit the hosts file and add a new blocking entry, open up your Terminal and type the following (You’ll be asked for your root password because this is a system file):

Step 2:
This will bring up a Nano box that looks like the one below. Yahoo has been added to block list as you can see. To block any other site, simply type it in the same format.

Note: one line, one site. And don’t forget to add “www” if the URL has been prefixed with “www”, or it will not work with Safari.

Step 3:
Click CTRL+X and Press Y in your keyboard to save modified buffer, and then press Enter to go back to Terminal.

Step 4:
Please run the following command in Terminal to take the changes take into effect:

• 1. If you are using Tiger, please type the following and press Enter:
  
  Quote
  lookupd –flushcache
  
  2. For Mac OS X 10.5 and later, please type the following and press Enter:
  
  Quote
  sudo dscacheutil –flushcache

Now the web site has been successfully blocked on your Mac

2. Use a third-party blocking tool.
By modifying the Hosts file we can block any sites we want to on Mac. But we do not suggest it when you are not Mac savvy enough. There is an easy alternative for you: using a third-party blocker. They are mostly be used as parental blocking. Take a look at Parental Control Software webpage which introduces a lot about parental blocking and monitoring tool for Mac and Windows.

  Funny

Keylogger software is used to monitor or record all activities occurring on a computer. This software is installed  directly by the user who wants to perform the monitoring - rather than hiding it on top of another software installation.
The following links would be helpful. They offer full reviews of keylogger software.

Mac Spy Software
- Stealth and undetectable monitoring
- Keystroke logging, Website recording
- Screenshot & application monitoring
- Email logging, receive logs by Email
- Ftp support, upload logs to FTP
- No need admin password to install(Standard Edition only)
- Record Passwords (Professional Edition only)

Remote Desktop Spy
- Spy on the remote desktop steathly.
- Take control of the keyboard and mouse remotely.
- Logs the name, time and duration of every program used.
- Records a keystroke log of what the user typed into each program.
- Saves regular screenshot images of the users desktop.
- Records the title and URL of every web page visited.
- Keeps a log of all folders and files created, renamed, moved or deleted.
- View the logs in real-time from another PC.
- Watch a live image of the users desktop without them knowing.

Mobile Spy Software
- Log incoming and outgoing number with duration and time stamp.
- Log every text message, including full text.
- Record urls visited by the mobile.
- Show summaries of all activities along with separate viewers.
- Uploads the data instantly before erasing.
- View logs online without touching your iPhone.

Nowadays, the soaring development of technology make our life more and more wonderful, computer becomes an indispensable part of everyone's daily life. So how to make the most appropriate use of it? We need the help of spy software.
BUT NOTE: Be sure the machine you install spy software belongs to you, or you will be landed in to court!