TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
TweetCaster - TweetCaster is a third-party Twitter mobile app that is available on Google Play and the Apple App Store.
Marketo - Marketo's powerful marketing automation software helps marketers master the art & science of digital marketing to engage customers and prospects.