Submitting a sitemap index to Google or Bing can tell them where to look, but small errors may prevent your URLs from being indexed.
In my case, the total URL count was 117 and the indexed URL count was 0, none, nadda. Whyyyyy!?
WRYYYYYYYYYYYYYYYYYYYYYYYYYYYY!
I eventually found that my sitemap links had "www." appended to the URLs, however the domain it was submitted under did not include the "www".
Now I also needed to submit the "www." and non-"www." version of my site to webmaster tools in order to get it indexed properly.
Changing that fixed the problem and it took about 3 days to start geting indexed.
There is also a nice checklist here, but it doesn't include the "www" note.
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