Promoter is a complex solution for you. You can send an invitation to your website to your friends (and other contacts) using your email addresses, also, you can invite your friends from social networks. So you can be sure that your invitation has been sent to maximum number of people. You can invite people from various email providers and social networks like: Facebook, Google (and G+), Yahoo, Mail.ru, Ya.ru, Odnoklassniki, LinkedIn, Vkontakte and Livejournal. How it works? - Easy. It doesn't use any hidden methods like parsing of DOM pages (as you probably know this method is pretty unstable), instead of this we use APIs. It means that we use API of every provider in order to get your contacts (so this solution will be most stable).