Data centers house servers, routers, storage systems, and other networking equipment to provide information technology services like email, web hosting, and application hosting. They have large power needs and specialized cooling systems to handle the heat generated by servers. Benefits of data centers include economies of scale, security, and redundancy to minimize downtime. Data centers are classified into tiers based on their redundancy and availability, with tier 4 data centers achieving 99.995% uptime. While data centers require specialized knowledge and equipment, cloud computing offers similar services on-demand with no specialized expertise required.