Or are virus writers just targeting IE more often?
Let me explain. Before I start, however, please note that this is not at all scientific. It is purely a rough theory on my part.
Let's say a car manufacturer made a car that would have premature engine failure 10% of the time. But that car only made up 5% of the total car market. The amount of failing cars makes up 0.5% of the market.
Now, let's say that another car manufacturer has 90% of the market. One of their cars would only have to fail 0.56% of the time to match the other company's failure rate.
What I'm trying to say is that IE has a MUCH bigger user base, and therefore is far more prone to have its vulnerabilities exploited before they are patched.
Mozilla has has a crapload of security flaws as well... Just google it.
http://www.google.com/search?hl=en&q=mozilla+security+flawsand then
http://www.google.com/search?hl=en&lr=&q=internet+explorer+security+flaws"Mozilla security flaws" produces 518,000 results and "Internet Explorer security flaws" produces 6,160,000. Considering that IE has somewhere around 90% of the market (this number varies depending on who you talk to), that's not too bad.
Just a thought I was having. Maybe it'll get other people thinking as well :-)
Also, try to keep any discussion civil and not just a 'Microsoft sucks! Linux rules!' thread. There's already plenty of those lately.