i am trying to start a reviews blog on comanies patent products like sony, panasonic or like these companies... i want to ask that can i put their products details from their site to my blog with "courtesy" or "source" tags and links to that posts from my blog? is it illegal activity or can i use it on my site?
You can't copy the content from another site and post it to yours without permission. Some affiliate programs will give you short canned product blurbs which you would be able to use. Hope that answers your question.