On the other hand, some users may wish to keep particular adware programs if their presence subsidizes the cost of a desired product or service or if they provide advertising that is useful or desired, such as ads that are competitive or complementary to what the user is looking at or searching for.
- ActiveX Controls: Microsoft Internet Explorer
- Browser Helper Object (BHOs): Microsoft Internet Explorer
- Mozilla Firefox Extensions: Mozilla Firefox
See also Worm.
Worms are "network viruses", primarily replicating on networks. Usually a worm will execute itself automatically on a remote machine without any extra help from a user. However, there are worms, such as mass-mailer worms, that will not always automatically execute themselves without the help of a user. Multiple vectors of spreading result in malware being typed as "Worm". A single vector of spreading will result in a more specific type. Examples: "Net-Worm", "IM-Worm", or "Bluetooth-Worm".