There is a fine line between abuse and just enough for your requests. The term spamming also applies to website submission processes. Each engine has different guidelines. Some companies own more than one search engine but use only one database. Some companies own and use multiple databases based on certain parameters.
Some search engines read other companies databases.
That is especially true with metasearch engines. Depending on the timing of the submission, the database owner and the schedule and activity of the robot, it can take anywhere from seconds to several weeks to get listed in an index. Rankings are based on actual search activity of millions of Internet users. New sites submitted or found during a crawl are listed in the search engine and given an opportunity to be found by searchers. Most engines weight favorably sites that users visit and spend time at for particular search topics.