In general if you don't have or use a particular piece of software then you can safely ignore the updates and or vulnerability notifications that you might run across.
Internet Explorer, on the other hand, is a special case. Use it or not, you must keep it up to date.
Internet Explorer Whether You Want It Or Not
The most obvious scenarios are these:
- Some websites work only with Internet Explorer. As IE's market share declines this is less common, but since businesses can count on IE being on every Windows machine they'll sometimes simply take the easy way out and worry only about IE when designing their web site. Want to visit their site? You'll have to fire up IE.
- Some software will automatically fire up Internet Explorer if you use online help or "Visit our website" types of features. Frequently they'll use IE even when it isn't your default browser.
Internet Explorer will come up, whether you want it or not.
But at least it's obvious.
Internet Explorer is More Than Internet Explorer
The problem is actually more complex, albeit it conceptually fairly simple: Internet Explorer is found in more places than just Internet Explorer.
IE is comprised of several components - an HTML rendering engine, internet access components, bookmarking functionality and so on. Perhaps the most important, though, is that HTML rendering engine.
I'll use that as my example.
When you visit a web page the contents of the web page are described in HyperText Markup Language, or HTML. Everything from references to images to the highlighting of words is specified in HTML. The rendering engine's job is to read that HTML, interpret it and make things appear as instructed.
For example, when the rendering engine sees "this should be bold" as HTML input, it produces "this should be bold" as its output displayed in the browser.
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