BackType is a conversational search engine that indexes and connects millions of conversations from blogs, social networks and other social media so people can find, follow and share comments.
Minggl is what’s called a social interaction manager and their toolbar makes it easy to manage information, communication, and navigation across (and independent of) social networks.
The Flock browser is designed to complement exciting social services.
4) Social Mention
Social Mention is a social media search engine that searches user-generated content such as blogs, comments, bookmarks, events, news, videos, and microblogging services.
5) Social Media for Firefox
Social Media for Firefox shows the number of Diggs, Reddit Votes, Stumble Thumbs and or Reviews, and Del.icio.us tags, Tweets, Sphinns, Mixx, and Tip’d votes so you can quickly see how popular certain content is.
This FireFox extension adds a tiny icon on the status bar that notifies you when your friends update their status. Also it has a small text input field to update your status.
PostRank provides detailed information on Tweets, stumbles, diggs, and FriendFeed all in a convientant single place.