The number of computers encountering one of the top 20 families of malware has dropped from 24 million a month to 13 million over the last two years, a Microsoft security official says. The data covers broad-spectrum malware and not mobile threats, he says. New companies into the antimalware field sometimes don’t play fairly, he said. But it is still recommended that consumers use an AV product, as it can block standard malware that steals login credentials or personal data. The situation may occur if a software company isn’t a pure play security vendor and offers other products such as a search toolbar.”]