The idea of social media being more effective than emails is now as persistent and wide-spread as that of Facebook or some other social network being better than a standalone web site. Both are equally incorrect, but I want to leave the latter for another post and bring to your attention a good article on why a mailing list is irreplaceable and how to build it the right way:
It’s especially a good read for those of you who haven’t started building a mailing list yet. As simple and straightforward as the process may seem, there are certain practices to observe if you want to avoid problems down the road. Double opt-in is only one example of those.