I'll post more about the actual web site I created another time; currently it's in alpha form running on Heroku. The web site is used for naming babies, the initial alpha-release is the girls' names only site EmilyOrEmma? which uses "Hot or Not" style voting and manages to incorporate in one page the Levenshtein distance, Metaphone algorithm and both item-based and user-based filtering.
But my biggest bug bear with baby naming web sites is the need to create an account. You can browse baby names all you want, but as soon as you want to do something like add a name to a list of favourites you are forced into registration. Or you don't have to register but anything you do is ephemeral.
For my site, I came up with a better solution: bookmark-based registration. If you visit the site you'll see at the bottom of every page a link to bookmark. This link is unique to you. It contains your user id and a hash which I used to prevent forgery.
Bookmark this link and you can return to your recommendations, saved names, etc. any time.