Cute Idea! However, you need to add more weight based on the number of tweets pertaining to the ICO. Your top rated company has a score of 89% but based only on 9 tweets. I would think that a company with a lower sentiment score but based on thousands of tweets should be more reliable and trustworthy. Also, does your algorithm diffrentiate between unique users?
There's a small boost to bigger exchanges in the ordering, but maybe I need to add a small decrease for some. I like to keep the actual score to be transparent (it's just positive tweets / (positive + negative).)
Only the latest tweet for each user for each exchange is used.