We are hearing so much about radical Islam lately. What exactly does this refer to? Was this not always a thing - where did this all stem from?

In as serious and respectful a manner as possible, I'm asking what the difference in beliefs is between the people who are blowing things up and those who are just everyday Muslims.

Do the beliefs state that jihads should occur, and that people should be killed under certain circumstances? Are the extremists actually following the Quran (or teachings) word-for-word and peaceful Muslims are ignoring parts of the religion? Is Islam peaceful, but some crazy people just spun it off into violent sects, and if so, do we know why?

Thanks for any insight. I honestly haven't researched the matter very thoroughly - my guess is that Islam is a peaceful religion but, like many others, there are crazies who decide they're to become the wrathful fist of their god.

I think some education on this topic could really help folks, myself included.