I'm attempting to focus on annotationg the organizations in twitter datasets mainly, title, organization, location and put. I'm trying to develop a set of features for this function. Any recommenadations on where and just how can one get a listing or database of such organizations to ensure that I'm able to use individuals to annotate the organizations.
You could attempt DBPedia or YAGO. The YAGO ontology is fairly huge you might like to extract the particulars you would like from this.