The AIndexify blog
Notes on getting pages into Google, and on telling the difference between a URL that was submitted and one that was actually indexed.
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Six reasons Google declines to index a page that looks fine
A page can return 200, render perfectly, and still never enter the index. These are the six causes we see most often, and how to tell which one you have.

Submitted is not indexed, and the difference costs you money
Most indexing tools report delivery and let you assume the rest. Here is what happens after a URL is submitted, and why the two are not the same.