It just takes one post or tweet to tarnish your business reputation.
Progressive Insurance neglected a client of theirs which lead to a heartfelt letter shared on Tumblr. Disregarding internet savy people and their ability to fact check the company went on the lie which lead to a bombardment of negative reviews on their Facebook page. As of today, the page has reviews disabled from being viewed.
In cases of disaster, do not launch sales to capitalize on others loss.
Be cautious with hashtags that, when combined, could inadvertently lead to the wrong impression.