FriendFilter - Auto unfriend tool for Facebook
Refined Twitter - A browser extension that improves the Twitter experience
Detox for Facebook - Replace your Facebook feed with PH, HN, DN and more.
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.
Keep My Friends - A lightweight, personal CRM to improve your relationships
ilo - Premium Twitter analytics