Ingredient API changes [13.03.2009]
There have been a few changes under the hood for ingredients recently. All the changes are designed to be backwards-compatible, but there are some neat new aspects to them, and the old way of including them is now deprecated.
Because page ingredients (where you're referring to an action on a particular page) are more involved than site ingredients (where you just drop a template from the ingredients directory into your code), we've split them up into separate calls: page_ingredient and site_ingredient.
Using the old ingredient method continues to work (and will probably never stop working), but we recommend that you move to this new API -- if for now other reason than to make it clear in your head what you are doing with an ingredient.
A bonus: you can now pass local variables into page ingredients, which was not possible before.
There's much more detail on how ingredients now work in the documentation.