I don't understand Why Google index new domain without any backlink and not even shown in public? The domain is not expired and no archive history at all. How Google find it?
some times if you post new content in your site and no competition for you means then automatically shown in results.
Google spiders find the new sites even without any backlinks. So indexing is possible without any backlinks.
Backlinks + submitting to the search engine manually can do the job. And of course, having a sitemap.
If it is a new blog made on wordpress platform, then auto pinging facility would have informed google of your existence! Regards, RightMan
I have had the same thing happen. I have americantravelblog.com and it was found. Even had several posts in it by people before I switched it over to a multi wp blog and locked registration while developing it. Now if I could ever find time to complete it....sigh