Some time ago I had the ‘pleasure’ of tagging 3225 photos. As often happens just as I finished someone suggested I take a look at Keyword Manager $19 because: 
“Keyword Manager introduces a brand new way of assigning keywords to your photos in a simple and efficient way. Keyword Manager is a plug-in for iPhoto that extends the functionality of your familiar iPhoto setup, and this plug-in will greatly enhance your photo management experience.
Whether you have 300 or 10 000 photos in your iPhoto library, organizing the photos with keywords will help you quickly find what you are looking for. Unfortunately, iPhoto’s keyword system is slow and cumbersome to use, as anyone who has tried it is well aware.
Using Keyword Manager to manage your keywords allows you to quickly and easily tag all photos in your library, regardless of how many photos you have and how many keywords you want to use. Since Keyword Manager uses iPhoto’s own keyword system internally, it is completely safe! Even if you decide to stop using Keyword Manager, all your keywords will remain!
In addition to offering a new quicker way of tagging photos, Keyword Manager allows you to group your keywords hierarchically. For example, you can have the keyword Paris as a subkeyword to France. Every time you assign Paris to a photo, France will also be assigned to that photo.
Keyword Manager is made to fit right into iPhoto, and it is designed to stay out of your way when you are not using it. It also helps you along when assigning keywords by offering suggestions based on your typing, taken from all previously created keywords, and the names of people in your address book.”
I couldn’t have said it better myself!!!
What I can, and will, say is that it is brilliant! I totally love this application – so much so that I am currently re tagging all 3370 photos in iPhoto. OK that is a bit of a fib. I am re tagging them all, but that is because I messed around with my iPhoto library! At the least the process isn’t anywhere near as painful as it used to be. The first time that I used Keyword Manager I spent time taking my existing tags (alright Keywords), all 237 of them, and filed them in Keyword Manager in a neat hierarchical folder structure. This time they are all there at it really is making the process so much better.
Take a look, I doubt you will be disappointed.
Aha! Told ya…
That you did sir – many thanks 🙂