Back to the original point..
Content is king..
I do not mean to trivialize the process of segmentation of customers. It remains one of the most difficult arts to practise. However, it is far from being the end of your campaign design. Targeting this finely segmented market (a collection of micro-markets each with their own needs, expectations and not to forget, business potential) with unique communication/ messaging and delivering it through the channel that best reaches them, is what is going to test you.
Who creates the messages? And who writes the content that will resonate with each of the target market and who provides the support points that will make the messages credible?
The internet made it easy to communicate but, it is akin to your being in the same room with your client. You still need to know what her individual needs are at that point in time and how to verbalize your solution to her needs.
When you have one segment to chase and only one message (one person to chase in a crowded room with one single thought in mind) to deliver, perhaps you can handle it. When you have many segments and as many individual messages/ benefit statements to deliver, it gets tough. Not the delivery so much but being ready with the right benefit statement.