We went to Apple desktops and laptops a few years back, and had almost no issues with malware or viruses until recently. I run Avira and AdBlocker Plus for protection against such things. Ive had several files flag and cleaned in recent weeks. About all you can do as far as home computers is load good virus and malware and keep it up-to-date. Im not too big on conspiracy theories, but these attacks on larger sites like those mentioned seem to coincide with 2 of the biggest on-line shopping days (Black Friday and Cyber Monday) of the year for those sites mentioned. And the attacks that are stopped outweigh those that actually cause outages by a 1000 to 1. Its a non-stop process addressing attacks.