This is technically a neat app, congrats for launching it.
However, I don't think many parents look to browse names based on prefix/suffix/infix. You may wish to add additional filters (based on what sort of census data you have).
Some ideas:
* Show only popular or only unique names
* Show modern names (recently popular)
* Show traditional names (long history)
* Show names with recent rising popularity
* Show names with historical popularity (that may have fallen out of use)
* Show names with similar histories (this would allow you to add a very important feature: "I like this name, show me related names!")
Finally, your graph feature is very nice; some of my favorite baby-naming books show this. But it's not very discoverable. You could make the name look more like a link, or show some graphics in your header as a demo.