Execution of Shia in Saudi Arabia: What Are the Implications?

Saudia Arabia recently executed 47 Shia including a leading Shia cleric. Why did this happen? What are the implications? The public execution was a slap in the face to Iran. Both Iran and Saudi Arabia are busy protecting their interests in the Middle East. The ring of Shia-controlled territory in the fertile crescent from Lebanon to Iran presents a real collision for the Saudis. This has been a brewing contest for some time, but now it has become public.