They’re two completely different products. That’s because both of them were acquired (not built) by Salesforce.
Marketing Cloud is actually ExactTarget (with some new social tools attached to it to the form the “Marketing Cloud”).
Pardot was acquired by ExactTarget as a requirement for Salesforce to, in turn, buy ExactTarget, back in 2013.
They both offer marketing automation solutions, in this sense: marketing automation is about timing. Marketing automation platforms allow you to build a relationship with those whose timing is wrong and won’t buy from you right now. And it helps you recognize when someone’s timing is changing in your favor.
Both Marketing Cloud and Pardot do this, but with a different focus.
Roughly speaking, MC is focused on volume and B2C. I know of lots of marketers that are using ExactTarget just for emailing. It’s good at handling tons of emails.
Of course, there’s a lot more going on there, such as social and SEA integrations, as well as the “journey builder” which allows you to automate follow-up actions (such as autoresponder emails).
My experience with it isn’t extensive, but I’ve found it a complicated program to work with.
Pardot is a product much more like Oracle Eloqua or. Sure, you can handle B2C with it, and all of these platforms can handle volume. But in reality, they’re better suited for B2B.
The real difference, to me, is that the “volume” tools help you focus on getting that first sale and then improving customer lifetime value. Which is the model for retail and anyone else selling relatively inexpensive products.
But if your product is expensive (e.g. consultancy, or software), it will require you to build trust with your prospect. You’ll need to accommodate his buying process, before he’ll consider spending thousands (if not tens-of-thousands) on your product.
The latter is where Pardot (and the alternatives I mentioned) shine.
From my personal experience, I’ve found Pardot much easier to work with than ExactTarget. It’s too bad support isn’t great for either product right now, which (if that’s important to you) might be a consideration for you, if you’re looking to get on board with either suite.
I first answered this question on Quora: