In terms of marketing a business, twitter is good to keep customers, instagram is better in attracting new ones. I have one twitter for personal, one for my business. I love the features (being able to create polls and have my friends vote on a decision.) I love the look of it and being able to keep in touch with my friends. :)

Twitter has taken over the world :) Place where you can share your opinion, read others. Start discussions and find ones with similar opinions. So many things you can do there. Just hashtag away :)