With google custom search users can easily search content on your website or blog. You can tailor search results according to your requirement. You can also monetize search results with google adsense for search.
Steps to Add Google Custom Search Box:
1. Go to google custom search engine and login with your google account.
2. Click on create custom search engine.
3. Give your search engine a name and description about your blog or website.
4. In sites to search block you can give url of any specific page of your site/blog (www.mysite.com/mypage.html) or entire website or blog (www.mysite.com/*).
5. Select edition and click on next to customize the style and finally get the code.
7. If you want to customize custom search box go to google custom search and click on my search engines and then click on control panel.