Not much: an “indexed” page is a page that has been crawled by a search engine spider and filed away in that search engine’s index for later use (note the italics), and a “cached” page is one that might actually show up in search results.

Apparently, getting your submitted pages listed in the SERPs is a multi-step process. First, the spiders need to access your home page and crawl whatever links it finds there. If they crawl, when they crawl, and how deep they crawl, depends on a number of factors, but let’s assume you have an easily accessible site rich with content and that the spiders have crawled every page. Congratulations! The next step is for them to decide whether or not to put the information they find into their index. Now assume they like your content well enough and decide to index all of it. Great! At this point, you can say that your pages have been indexed.

So what? Big deal. By this I mean it’s good to be indexed, but it’s not enough because this part of the index is not offered to the general search public. That is, your pages have not been cached, but all of the textual information from your pages (urls, titles, tags, snippets) have been indexed. Of course, this textual information has been cataloged, categorized, filed (indexed!) based on the keywords you chose when you built your pages and on the relative focus and interaction of those keywords on those pages, and it has been ranked accordingly, but this part of the index is not meant for the SERPs and is not accessible to surfers. This is web page purgatory. La-la land. The Google “sandbox”. It’s a way station for lonely, unused web content. A word bank from which search engines can withdraw money. Okay, no more metaphors. The point is that the search engines will not offer this content to web surfers at this stage. Google may tell you, “We have just indexed your pages!” Great, but they will NOT show up in search engine results. They may eventually arrive, but not yet.

The last step in the process comes when the search engines decide that your information (which they have already indexed and so have access to) might actually be of use to someone. When that happens, they will take a “snapshot” of the page (save or download it) and store the file away in their index of cached web pages. This is a completely different index, or more accurately, a subset of the original index, but it is safe to say that these cached pages qualify for inclusion in the SERPs, and now your potential customers may be able to find you. The search engine gods have gone one step beyond indexing your content and have now indexed the actual pages, which they will present to web surfers in their full and complete glory. It’s really just a matter of semantics. Your content has been indexed the whole time, but that doesn’t guarantee inclusion in the SERPs. Only further indexing (caching) will do that.

So, a search engine could have all 1,000 of your pages “indexed” but only 50 or so “cached.” This explains the strange numbers you get when you do a site search (site:yourdomain.com) and notice that the number at the top differs, often drastically, from the actual results on the page. This is to be expected because there may be several pages on your site which the spiders have crawled and indexed, but which the search engines did not find meaningful or useful enough to cache. You may even agree with them. A “thank you for ordering” page may get indexed (spiders are not overly picky eaters), but it probably shouldn’t get cached and it probably won’t. But the search engines figure (or were told to figure) that this page may become useful someday and so keep it in the index uncached. They will likely revisit the page on subsequent crawls to see if any changes have been made and to reevaluate the situation.

Sometimes a search engine will just stubbornly refuse to cache a page in their index which you know for a fact is very useful and which you know your customers would just love

SEO is not a one time event but a continuous process. Your initial attempt at search engine optimization for your website will almost certainly not be your last. Most site owners will tell you that there is always room for improvement. Search position and page rank are not static but are constantly changing and fluid. Trends change, industries change, markets change, search engine algorithms change, and website owners who neglect to maintain and periodically “refresh” their site after it is built and established run the risk of becoming irrelevant.

Competitors are forever attempting in several ways to outdo one another for placement in the SERPs, and an increase in page rank for one of your competitor’s pages unfortunately means a relative decrease for your own. This happens constantly as competitors come and go and work out their own SEO issues. Because of this, it is inevitable that your search position will degrade over time.

It is important to keep providing fresh content and to periodically update that content. This could be as simple as providing new offers, coupons and banner ads and tweaking your site’s titles and tags, or as much as adding whole new pages of indexable content. Search engines love finding new links to crawl and comparing the pages they find with the content they already have. Again, almost any content on the web will become stale over time without frequent updates.

Constant monitoring and maintenance of your position on the web is therefore a must, but what exactly should you be thinking about when the time soon comes to address these issues? Here are just a few considerations:

SEO Reports – Careful monitoring and analysis of your current position is important. Weekly reports containing search results by keyword or by search engine can tell you how visible your site is to the search engines and to your customers. They can also show you how that visibility fluctuates over time and give you valuable information you can use to stay on top of your competitors.

Traffic Reports – It will do you no good to place well in the SERPs for a keyword or phrase no one uses. It is important that the keywords you do place well for actually bring traffic to your site. Most traffic monitoring software can tell you the keywords your visitors are using to find you, and used in conjunction with SEO reporting software it is possible (after a certain amount of trial and error) to zero in on the keywords that give you the best placement and bring you the most traffic.

Competitive Analysis – If your competitors consistently outrank you for your most important keywords, then it is important for you to understand why and to remedy the situation. See what primary and secondary keywords your competitors are using and how they are implemented. Analyze their content and compare it to your own. Check other ranking factors as compared to your own, especially backlinks (a.k.a. inbound links). Use a backlink checker such as the one found here <http://www.iwebtool.com/backlink_checker> to discover who is linking to your competitors. You might even try getting a link for yourself from these same sites. However you obtain backlinks remember that this is the single most important factor contributing to your site’s page rank and position in the SERPs.

Navigation and site structure – Make sure your navigation menu is spiderable and that your anchor text includes the primary keywords contained in the target page. Validate your code. Messy, illogical, or poorly structured code can make it harder for search engines to crawl your site. Properly naming (or renaming) files and folders can also have a huge impact on a page’s rank because this will show up in the page’s url. Most search engines give a lot of credit to a page which contains keywords in the url because it is a very good indication of what the page is really about. “Page rank passing” is another consideration regarding site structure. Web pages share their page rank status with the pages they link to. Every link from one page to another is a “vote” for that other page. Proper internal linking structure will ensure that page rank is evenly distributed throughout your site and directed at the pages you feel are most important.

These things all take time and at the risk of sounding redundant, SEO is an ongoing process. Many SEO experts claim that the age of a site contributes to page rank. This is not technically true. The age of a site does not determine page rank, but it is a necessary correllary to page rank because site owners who have addressed all of these issues and have built and established a well-structured, well-linked site will undoubtedly have to spend many months or more doing so. These things take time. Not just the time it takes to edit a page or add a new page, but also the time it takes for those changes to get crawled, indexed, and cached. Google warns that it may take 4-6 weeks for a page edit to show up in the SERPs (whether it’s a single word on one page or several words on several pages). In my experience, you can take them at their word on that.