indexkings.com
IndexKings is a free rapid URL indexing service that submits user-provided URLs to over 15,000 statistic sites to generate one-way backlinks and speed up indexing by search engines including Google. It also offers additional tools including a ping service and link checker, and had indexed over 2,147,483,647 URLs as of the snapshot. The site also lists a paid Quora profile submission service priced at $2.