Yes @allisonmarry SEO and Social Media Marketing is a best option when compared with social marketing but that's doesn't mean that you can neglect the email marketing because sometimes it do yield good results ! And when I say this means we have tried that thing at a personal level and its' a good option to bet into!
Email marketing is one best and successful way to generate leads. And yes no doubt that almost 30% lead comes from email marketing only. But it's all depend on which industry you're dealing with? and what kind of customer is? If you're in B2B industry than email marketing could be succeed.
I think traditional email marketing is dead (buy list, send mail) and also dangerous. Building your own list of customers is another matter all together and obviously can be very effective.
Once you have your customer list, don't over send because most peoples inboxes are already full of spam. So, send out quality material and specials like a normal business (brick and mortar) would and the results will be much better.
For me, I just skim over my inbox these days, looking specifically for certain senders, clients, friends, etc. and everyone else goes on the mental ignore list.