My Fave: Crowdbooster
Crowdbooster show you how you can better reach important influencers, create content that resonates with your audience, and send content at the most effective times.
Bring your Facebook Pages and Twitter accounts together to have a complete view of your marketing efforts in one centralized place.
The platform will also allow you to calculate the best time for you to send out a new tweet or your Facebook posts. Find out your Facebook Fan growth, number of impressions, top Fans and more.
Free personal account (1 Twitter account and 1 Facebook page).
Find out more on crowdbooster.com