HitforHit You will get 100 coins as sign up bonus.
Socialclerks You will get 50 points as sign up bonus .It has one good feature that you can follow user in your interest or in your country .For example if you want to follow bloggers ,you can do it . It is best site to getting targeted followers .
Share-ex You will get 200 sign up bonus which is equal to 20 Fan page likes
http://likes-exchanger.com (new and a lot of bonus coins )
Final Words :
Social signals will always be a circle ranking factor . The above listed website are the best social media exchange sites . Simply sign up ,like other post,page and get likes back . If you want more social signals just buy some points and get social signals without any problem.
You can also buy social signals from seoclerks at very cheap price.
For Example You can purchase about 2300 social signals in $3 from