Inscovery - Discover unique Instagram users that share your interests
Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.
Roundio - Explore what people posted to Instagram or Flickr near you
Tweetdraw - Tweetdraw is an online tool that provides an easy way to pick a winner for a giveaway, having a quick Twitter Quote Draw, Instagram Comment Draw, and Twitter Retweet Draw.
Instaround - A simple app to find Instagram photos and people around you.
Twesocial - Twesocial helps you grow your twitter with real twitter followers. Real results, real people.