Enjoy The Google Honeymoon.

When a new website or a new page is added to googles index, it will get an artificial boost in rankings.  This gives users a chance to see new sites and popular topics, such as news stories, topics and new websites. Some of the older mature, top ranking sites, may not be as relevant.

When google first indexes a new url, they will boost that website on page one of the SERP's for hours, days or a week for keywords that google thinks are relevant, but the site should not be in that position because there are not enough quality backlinks. This is why its coined the google honeymoon, enjoy it while it lasts.

Its a great feeling when your site is ranking first place for many different keywords within 24 hours, but to boast about it, would show inexperience. Because the honeymoon wont last forever! You still need to build good quality backlinks.

Remember, its very normal to get good rankings for a few days and/or weeks, don't get annoyed when your rank has dropped to the tenth page, where it belongs.