One of the magento based website had strange issue. All rules in the admin > Promtions > Catalog Price Rules were inactive. But still some products were displaying as sale items. So ran mysql code listed below to find out what was happening.
More»
Today because of magento bug when I saved payment info on client's site, it replaced all payment info on database with encrypted values.
From today onwards I am going to apply these rules to fix issues with SEO.
Magento admin / System / configuration / General / Web / Auto-redirect to Base URL / Yes (301 Moved Permanently)
Also, add robots.txt file with below content.