Pack.org is a great alternative to http://thunderclap.it. It operates differently to Thunderclap as it is meant for either an ongoing campaigning or continuous communication with your supporters as opposed to a one-off situation. Unlike the other alternatives that were shut down due to the same API changes to Facebook, Pack.org does not automate posting. Rather it allows you to create and schedule posts for Facebook and Twitter and then contacts the members of your Pack (what they call their groups) for you via email and SMS to prompt them to post. This allowed them to continue to operate while the others were taken down. This has several benefits as it promotes an opt-in mentality for users and allows them to customize the message before they post giving further authenticity to the messaging you are trying to get across. As we all know authenticity is king when it comes to social. They offer personalized customer support to get you started, holding your hand through the key setup and onboarding phase. While this is not a free piece of software, they do offer a free 1 month no strings trial to all signups. Their asking price right now is 250 British Pounds per month. Some key features: Custom URL for your Pack to make it easy to onboard new Pack members. Custom URLs for all your Howls (what they call posts) for easy tracking. They show you how many connections your Wolves (Pack members) have and how much each of them generates on each of your howls. SMS and Email reminders to your Wolves for Howls. The ability to schedule months in advance for your content a la Hootsuite.