Why Anti Virus Update Every day?

You might asking why anti virus program like Avast, Kaspersky, Avira and AVG update their definition database almost every day? It is because almost every day new variants of threats including spyware, virus, adware, Trojans, worms, keyloggers, backdoors, hoaxs and rogues are emerged on the Internet. By updating the malware/threat definitions database, it increase your anti virus program's detection and removal rate of new kind of computer threats and keep your PC from their attacks.