How Did the Spread of Islam Affect the World?

From: http://www.meccacenter.com/meccacenter/index.php?option=com_content&task=view&id=23&Itemid=18

The Muslim community continued to grow after Prophet Muhammad's passing (may God bless him and grant him peace). Within a few decades, vast numbers of people across three continents-Africa, Asia, and Europe-had already chosen Islam as their way of life.
One of the reasons for the rapid and peaceful spread of Islam was the beauty and simplicity of its doctrine-Islam calls to faith in only one God and to belief and acceptance of all God's messengers. This, coupled with the Islamic concepts of equality, justice, and freedom, resulted in the formation of a united and tranquil community. People were free to travel from Spain to China without fear, and without crossing any manmade borders.
As millions of people embraced Islam, they brought with them the heritage of ancient civilizations from lands such as Egypt, Greece, India, Persia, and Rome. Muslims cherished these cultures, their sciences, and the collective knowledge that they had to offer, and they took great pains to preserve their libraries and to honor the scholars residing in their cities.
Many Muslim scholars traveled to these cities seeking knowledge. They translated volumes upon volumes of philosophical and scientific works into Arabic from Greek and Syriac languages (the languages of Eastern Christian scholars), from Pahlavi (the scholarly language of Pre-Islamic Persia), and from Sanskrit (an ancient Indian language). As a result, Arabic soon became the world language of scholarship, and people from all over the world migrated to study in Muslim universities. For centuries to come, Arabic remained the most important scientific language and was the repository of much of the wisdom and sciences of antiquity.
The achievement of scholars working in the Islamic tradition went far beyond mere translation and the preservation of ancient learning. These Muslim scholars built upon the knowledge of the ancients, all the while forwarding their own scientific endeavors. These very advancements were a direct cause of the European Renaissance.
Muslims excelled in art, architecture, astronomy, geography, history, language, literature, medicine, mathematics, and physics. Many crucial systems such as algebra, the Arabic numeral system, and the very concept of the zero (vital to the advancement of mathematics itself), were formulated by Muslim scholars and thereafter shared with medieval Europe. Muslims invented sophisticated instruments that made the European voyages of discovery possible, including the astrolabe and the quadrant, as well as detailed navigational maps and charts.