AOL Turns 25

Network Operations Center
Up against the ropes, AOL fought hard to regain its standing. Addressing user complaints about spam, the company launched an initiative to reduce the amount of junk mail that besieged its users' inboxes. In 2003, the company boasted that it blocked 2 billion spam messages in just one day. In 2005, the company changed strategies to allow users to access most of its services free, thereby shifting its business model to an approach that relied more on advertising than subscription fees.

• A Brief History of the Computer