A drip campaign is a method used in direct marketing to acquire customers through lead incentive programs. It involves repeatedly sending marketing information to potential customers for longer periods of time to nurture potential customers or leads through the marketing funnel.
Drip campaigns are usually done by email marketing, where pre-written content is sent automatically at set times to engage these contacts.
There are online tools available that can automate the "dripping" of your content, such as marketing automation from Hubspot, Marketo, Eloqua, Pardot, and others. which allows the user to automatically publish pre-written emails sent through timely campaigns. These drip campaigns often have end goals to bring back more leads in the funnel or older leads in the funnel and pipeline.
Sending this information over and over to the same potential customers will expose them to your brand over and over again, which will increase your familiarity with your brand and allow you to engage with them again to bring them back into the marketing and sales funnel. Their repetitive exposure can lead them to buy your product.
Social media and email campaigns are useful channels for drip campaigns for the potential use of a larger user base.