Hi Alastair - it didn't seem that your question about "What do these four words actually mean" was answered. I wanted to share a bit that might help. When you go to places using your web browser, most of them store little nuggets of information about you and your computer. It's not as scary as it sounds - those nuggets let the sites know you've been there before so it makes logging in and preferences a little more smooth.
Another term you'll hear is "history." That's the list of places you've been in your browser. That helps because if you can't remember the exact address for a site but you know you've been there, you can go to your history and choose it off the list.
The third term -- which I find the most critical -- is "cache." Every time you visit a web site, bits of the text, images, and anything else on the page are stored on your computer as temporary files. It helps the computer process faster by pulling in those snippets of stored information rather than traveling across the internet to pull in a fresh copy each time.
Personally (and what I recommend to my faculty), I never clear my history and cookies, but the cache (temporary internet files) are a different matter altogether. They clutter up your computer and when they get bad enough, cause weird funkiness to happen. If you're old enough to remember slate chalkboards, you know that the writing at first could be erased clean, but after a time, when the teacher erases, it began to leave shadows of the text, finally to the point where the writing couldn't be easily read and the boys with a bucket and sponge had to wash the blackboard. That shadow writing is like a cache -shadows of previous things that finally interfere with what you want to do. I recommend that you clean your cache (temporary internet files) at least once a month -- more often if you use your browser heavily. For example, I clear my cache at least once a week and anytime I have been in-and-out and in-and-out with a project frequently.
Hope this helps.
Cindy.
