Short answers, pulled from the story.
The Continental System was a large-scale trade embargo declared by Napoleon I against the British Empire, running from the 21st of November 1806 until Napoleon's first abdication on the 11th of April 1814. The Berlin Decree of that November date forbade any European country allied with or dependent on France from importing British goods or maintaining any connection with Britain, including mail.
After repeated naval failures, including the defeat at Trafalgar, Napoleon could not challenge British sea power directly. He believed Britain depended completely on European trade for its prosperity, so he aimed to destroy the British economy through isolation. He hoped economic collapse would force Britain to sue for peace and leave him free to consolidate control of Europe.
It largely failed. Extensive smuggling undermined enforcement from the start. British merchants found replacement markets in North and South America. The system damaged French and allied economies nearly as much as it hurt Britain, giving Napoleon's allies incentives to ignore his directives. Napoleon's St. Cloud Decree of July 1810 partially reversed the embargo, admitting it had hurt his own economy more than Britain's.
Two invasions directly tied to enforcing the embargo ended in disaster. Napoleon invaded Portugal in 1807-1808 when it refused to comply, igniting the Peninsular War, which tied down large French forces indefinitely. Russia's withdrawal from the system in 1810 was a key reason Napoleon invaded it in 1812. That campaign ended in catastrophic retreat and set the stage for his abdication in 1814.
Britain's orders in council, issued in response to Napoleon's embargo, threatened punitive measures against any neutral nation trading with France. The United States responded with the Embargo Act of 1807 and later Macon's Bill Number 2. These measures proved more damaging to American merchants than to Britain. Combined with other British provocations, including impressment of sailors, they led to the U.S. declaring war on Britain in the War of 1812.
The industrialized north and east of France and Wallonia, the southern part of present-day Belgium, benefited. With cheaper British textiles excluded from the market, local manufacturers faced less competition and saw profits rise. Italy's agricultural sector also flourished during this period. These gains were unevenly distributed, however, and trading-dependent economies like the Netherlands suffered greatly.