Malware, an abbreviation for "malicious software," encompasses a range of harmful software types, including viruses, trojans, spyware, and adware, each with its own distinct threat to users. Spyware is designed to covertly monitor user activity, while data mining involves the automated analysis of large datasets, which can sometimes infringe on privacy. Adware finances itself through advertisements but can also refer to malware that displays ads without user consent. A Distributed Denial of Service (DDoS) attack involves numerous sources overwhelming a service with traffic, rendering it inaccessible to legitimate users, similar to a crowd blocking access to a site. These concepts are part of a broader discussion on IT security, which is further explored in the IT Sec FAQ series.