How do you measure the success of your digital marketing campaign?

Views and click-throughs can help you know how strong your marketing message was, pushing people to click and know more about your products/services.
Whereas the sales figures can tell you to what extent your whole campaign was successful.

It totally depends on your goals and objectives, since success; can be measured by comparing campaign results with goals.
For instance measurement of campaign with a goal to increase brand awareness of a certain product, totally different than measuring a campaign with a goal of lead generation of the same product, the first one will have the reach and visits as the main measurement, second one will mainly have the sales volume as the main measurement.
If we are discussing the management of thee campaign to be successful; then it is another story, which will need a proper customized measurement framework, to know where were the bottlenecks and how to eliminate them for the best marketing funnel flow.

the only way to measure your campaign will be through the feedback which you get may be you can go through survey

Success comes in many forms .
.
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including digital marketing success.
Firstly we need to define what are your goals? What specifically do you want to achieve from the digital marketing campaign? This could be things like: Sign Ups To A Service Or Membership, Brand Awareness Or Traffic Coming From Brand Related Terms, Greater Social Following And Audience, Increase Overall Sales, Sales Of A Particular Range etc...
Once you have the Goal in Mind you can take help of analytic like Google Analytic, Mediamind Tracking, ZEDO tracking etc which can help you in assessing the result you get out of the digital campaign.
Then it becomes easy to access whether digital campaign is a sucess or not...

Every campaign should have SMART Goals and KPIs, that should be aligned with the institution's strategy.
While these goals could vary, using analytic tools help you measure the performance, and integrating the generated leads/sales with your CRM helps you calculate the ROI (Return of Investment) The beauty of Digital Marketing is that it is Measurable, Accountable, Flexible and Transparent, hence why print and TV Ad spends are shrinking :)