It's just text with a write-on effect applied, and a simple camera move. Time-consuming to build, but not complicated.
The way to do it would be to create the final image first - just type all the names in the various handwriting fonts and rotate, size and position them as necessary to build the phrase "Who's Counting On You?" (or whatever you want it to say).
To make the names write themselves on you'll have to use the technique described in this tutorial: Draw On Text. This will be the most time-consuming step. You might find that a better workflow would be to create a new group for each name, type the name, *then* create the write-on effect for it, *then* resize/rotate/position the group.
Then you simply add a camera, zoom in to whichever name you want to start with, and do a slow pull back to reveal the whole phrase. Adjust the in-points of all the names in the timeline as appropriate so they don't write on while they're still off-screen.
I think the names were written using animated brush strokes with the write on effect and using a tablet makes this pretty easy. I've used the technique in that tutorial and it gets messy when a letter loops around itself or lines cross. Like with a capital A. If you don't have the mask channel exactly right, then parts of the horizontal line will show up when you draw the first lines. Getting the mask channel right where it needs to be is the real time consuming part.
I also think the majority of the final image (that didn't require animated writing) was made in PhotoShop and then the parts were filled in using motion.