ahem... you appear to be all wrong (lol - don't wanna sound too harsh)
The point is, if you keep submitting your website through a website/script then a search engine will think that you are spamming them, however, as long as you do it manually then a search engine will love it. The point is that search engines like:
a) Sites that are updated often
b) Sites with history
Now, if your site gets updated every day, then a search engine is likely to revisit your site everyday of its own accord, but if you have a website and you haven't updated it for a month, or even a week or so, then I would resubmit it. This tells the search engine that you are still there working on the site, it also tells them that there is new content that it needs to look at. Lastly, if your website was already in the index of websites then it sees that the website has a history and will rank your site higher.
Tom