The whole point of SEO is to appear on the SERPs. If Google doesn’t even realize you are there, you could have a major problem. There are several reasons you could be passed over for indexing, and we will cover the main ones here.
1. If you have just submitted, it might take some time for you to be indexed – anywhere from a few days to a few weeks or even more. Be patient, and wait for it.
2. You don’t necessarily get notification when you are indexed by a search engine, so check back and make sure you are truly not indexed before getting worried. Some tools are available to help with the checking process.
3. Make sure that your pages are all uploaded before you submit them. It is a possible mistake to make – getting the cart before the horse! Again, if you mistakenly submit before verifying that your pages exist, or mistype a url, you could go for some time before realizing your error.
4. If you have no external links, you might remain unindexed until you procure some, or you might be indexed and later dropped for lack of links. If this happens before you have a chance to build good connections, simply resubmit after you have acquired some solid external links.
5. Host on a isolated IP if possible. Sometimes you can get into trouble just for being hosted on a server that a banned website is sharing. You get a taint that makes the search engine ignore you.
6. Watch your urls. There are several flags that can occur that will keep you from being indexed, as some extensions are assumed by Google to be binary and therefore not worthy of attention. Avoid ending your url in ‘.ext.’ or including ampersands or question marks in your url.
7. Use a reliable hosting service that is up over 99% of the time. If a spider pays you a visit and your site is down, you could get yanked from the index completely.
8. Avoid black hat SEO. If you have suspicious redirects, the engine may suspect you of cloaking, and white on white text is regarded as spam. Either of these actions can lead to Google refusing to index your entire site.
9. Don’t submit all at once! Pace your submissions and submit the most important pages first. Otherwise the search engine may suspect so many simultaneous submissions from the same domain, and ignore them.
10. If you have checked all the above, and your site is squeaky clean, re-submit. It’s possible the engine lost your submission. Yep, bugs and technical errors can trip up even the mightiest search engine, so give it another try.
The main reason sites and pages are not indexed on Google is suspicion of dubious tactics to trick the spiders and Googlebot or intentional manipulation of Page Rank or the SERPs. Remember to ‘not be evil’, and you should have no trouble getting indexed!