Unethical Business Practices
High rankings on search engines is a goal that every webmaster wants to achieve. If your website has high rankings on Google for a good keyword then your website will get a lot of attention. Your competitors also know that and some of them may use unethical business practices to sabotage your search engine rankings.
These are some of the tricks that your competitors may use against you.
1. Your competitors might use your name to create spam
All major search engines use links to calculate the ranking of web pages. It's not only the number of links that counts but also the quality. Your competitor might add your website to several spam linking schemes to hurt your site.
In addition, your competitor might use your website URL for spamming in online forums, social network sites and blog comments. Although it's not you who is spamming the websites, it will be hard to prove that you're innocent and social network sites might ban your website (which will have a negative effect on the link structure of your site).
2. Your competitors might peach on you
Did you buy links from other websites to improve your search engine rankings? If your competitor finds out that you use paid links they might inform Google and your rankings might drop. As you know Google doesn't like that at all.
The same can happen if you use any unethical (Blackhat) SEO method on your website. If your competitor finds out and informs Google then it's likely to affect your search engine rankings.
3. Your competitor might send a copyright complaint?
If a search engine has been notified about a copyright infringement on your website then the search engine removes the page from its index for 10 days.
If your competitor files a copyright complaint against you then your website can be temporarily removed from the search results.
4. Your competitor might create duplicate content
Search engines don't like duplicate content. If more than one web page has the same content then search engines will pick one page and drop the rest.
If your competitor creates duplicates of your web page content then these duplicates might get better rankings than your own site. Of course, this can cause legal problems for the person who duplicates the content.
Unfortunately, you cannot evade or stop unethical competitors from using spam techniques to harm your site but you can avoid being banned for using spam techniques on your web pages. Only use ethical search engine optimization methods to get high rankings on Google and other major search engines.

