Which keyword research tool you need to success in your affiliate marketing

Keywords research is not the most important tool to success in affiliate marketing but its fundamental tool to success and if you would like to build an online business in today's competitive environment it's very important to choose the best tool that can help you.
Nowadays, there two type of keywords research tools:
1. desktop software
2. web based software
To choose your basic tool there many criteria:
- You must understand how these tools work, which their source of information to build their data base
- Determine the purpose that you will use these tools because every one of them has their features and benefits.
Take attention when you use free tools because they can give worthless information.