Anytime you search for something on the web and get the results page for what you were looking for, you are actually viewing part of the search engines Index. The SEO term for the results page or index page of a search engine is referred to as the Search Engine Results Page or SERP. Let’s look a little further into the Index and Indexing.
To get a better idea of exactly what the SERP is, take a look at the picture below. It’s the SERP for the keyword “small business blog marketing”:

It’s actually pretty simple. Indexing sort of means what is sounds like. Think about a book, when you want to find a certain part of page you generally look at the Index as opposed to aimlessly flipping through the pages trying to find what you want. An Index is basically a hierarchy of information.
When you’re talking about a search engine it’s pretty much the same thing. Except if you thought a 1,000 page book was a lot to go through, imagine a couple billion pages that can be searched in under a second. Well, welcome to Google.
Google has a huge Index as I just said. It’s always changing and growing but it’s usually packing around a one hundred billion or so pages. So Like I was saying it really is just a big book except you have to tell it what you want and not just see what it has to pick from.
Indexing is the process of getting your page into Googles Index. I previously stated that you don’t get automatically indexed in Google or any other search engine. Google is the best search engine to find information and for people to find your information so it’s good to be in there.
It doesn’t care if you made the page(s) two minutes, months, years of decades a go. Some of the older and other search engines won’t even put you in the index until your page or site has been on the net for at least a few months but usually a few years.
On the other hand, Google’s Index is always changing. What’s hot one hour sometimes is not so hot the next hour. Again, this like anything else is good and bad. You can search for something at 11 a.m. and it’s # 1, you can then search for the exact same thing and find that page has been moved down to # 1,999,823.
Google is all about relevance and popularity. In a lot of ways Search Engines are like teenagers. They highly value what other people think and the more popular and “in” you are, the better you’ll be treated.
I like to think of it like Day Trading and Long term investing on the stock market and other financial sectors. Google is like Day Trading and Long Term Investing. You can get your page in Google the same day you make it and it can be #1, for a day or for a year or forever. Yahoo on the other hand may take several months to get in but once you’re in you can hold your rank pretty well.
So once again and finally, I’ll just sum up what the Index of a search engine is and what Indexing is. The Index is what the search engine already listed or indexed and Indexing is when you add something to the Index or listing. Simple right? I told you so…