Disclaimer this post is for educational purposes only. Actually doing this is highly illegal and immoral and I don’t not condone this strategy in the slightest. This post is to enable you to better protect your own site from being a victim to this sort of “attack”.
If a site is ranking above you in the search engine one way that you can “level” the playing field so to speak is to fill its database full of junk in doing so this will use up all the memory allocated to the database taking down the site.
Just about all sites use databases to store their data and just about all sites allow some form of user submitted data making them vulnerable to this sort of attack. Filling a database full of junk is quite simple all you need is Imacros which will allow you to record browser actions and then replay them.. over and over again allowing you to fill the database full of junk via forms found on sign up pages, contact pages, user reviews and even just simple newsletter subscription forms.
It is a big task and quite mean but it is achievable. On average website hosts will allocate around 2gb of database storage per website. This equates to 2.5 billion characters worth of data, whilst this is a heck of a lot of characters to submit to a website you can quickly fill up a sites database by finding a form on your competitors website that allows you to post unlimited amount of characters. By recording a imacros that generates random 1 000 000 characters worth of text and submitting it within 2500 submissions a site will be taken down. Not all website forms will allow you to submit 1 million characters however, some forms may only allow you to submit a couple thousand characters with some even limited to a couple hundred if this is the case you are going to have to increase the time spent submitting data (increasing the chances of you getting caught and the website owner adding a captcha to the form) or increasing the number of imacro threads eating away at your cpu and bandwidth. At the end of the day it is all a numbers game but once you do reach the magic number of allocated database memory the site will not run and will be rendered useless meaning google will demote the site in the search results and you will be able to rank above them.
If you are a victim of this kind of attack one way that you can help to stop this from happening to your site would be to add unique captcha to your sites forms (one which only a human could complete), it is as easy as that)!