Little Snitch network monitor
Internet is very important to have a good workflow these days. But, when using your computer, you sometimes doing things without noticing that you are online.
It is quite normal for me, and assuemedly to you, to read mails, check RSS feeds, look for software updates, surfing or consulting search engines, dictionaries and translations.
Everytime you are doing some of those tasks your ISP (internet service provider) is contacted to grab those information.
The windows users draw the shortest straw, because there are thousands of viruses and trojans existing. And with every internet request you are taking a journey into danger. The integrates OS X firewall is a really great protection.
In my humble opinion the most hazardous risk are phishing mails, infected websites and applications calling home.
Objective development has created a great firewall software called Little snitch. It is highly configurable and it really snitches very good.
No application will call anywhere if you do not grant it.