RiteTag is the perfect tool to know exactly what hashtag will propel you into trends. This tool will let you know directly the hypothetical impact of the use of a hashtag and whether or not it is good to use. You can even compare two key words to find the one with the best chance of working, useful when using plurals.
Choosing a keyword that is unpopular for being too complicated can be the difference between a viral post and an ignored one. RiteTag gives you information and advice on good practices. With more lists indicating the popularity of many hashtags, you will sure to hit the intended target.
Ritetag also provides a system of alerts telling you if your keyword is popular within Twitter. Ritetag offers registration via Facebook, twitter or a browser plugin.