MEMPHISBIRD  I would have contacted the developer directly, but I don't see any way to do that on the website, except for the forum that is filled with spam. I tried to install the latest update and it tells me there is "no valid iPhoto version on this system." Additionally, the modification date on the downloaded 1.5.3 installer says March 29, 2009. Is it really an update? Do I have the correct file? Do I even need this update? My current version is working just fine.  
(Version 1.5.3)

UMIJIN  Hmmm... The updater wouldn't work with iPhoto '06 (said it couldn't find a compatible version of iPhoto). The previous version had this limitation, and the MU description suggests it still works with '06.  
(Version 1.5)

MAROOK  Ahh, that is so nice - back to tagging my photos!  
(Version 1.5)

ANDREW SCOTT  Does anyone know if it's possible to get this version working with iPhone 8.0?  
(Version 1.4.3)

DISPLACED  I got it to work in Leopard :)

Look in /Library/InputManagers/ and ~/Library/InputManagers and delete SIMBL.

Re-download the latest SIMBL from http://www.culater.net/software/SIMBL/SIMBL.php and let it install.

Re-install Keyword Manager.

If you have anything in ~/Library/InputManagers, move them to /Library/InputManagers.

Leopard will only run InputManager plugins from the all-users Library.   
(Version 1.3.2)

WINSTEPH  Great plug-in. But it won't load in v. 7.1.  
(Version 1.3.2)

QUBEX  The latest Apple iLife update + Leopard install has killed Keyword Manager. It no longer appears in iPhoto. Uninstalling/reinistalling doesn't work.

Any idea when it'll be fixed? It has become second nature to me by now, I can't work without it!  
(Version 1.3.2)

OLLIE  Literally a flawless keyword plug-in for iPhoto. Make's iPhoto complete. Look forward to seeing an update for iPhoto 7!  
(Version 1.2.1)

GAVIN CUTSHALL  This is an awesome tool, and I am a registered owner.

Please release an iPhoto 7.0.1 compatible upgrade so I can enjoy all the KM goodness with iLife '08.

Thanks!  
(Version 1.2.1)

DWEINGART  I was a longtime fan of the free Keyword Assistant program, so the developers of Keyword Manager had a high hurdle to overcome to convince me to go from a free product that I liked to a shareware product.

Well, I'm a registered user now. This program has such a fast and easy interface that it makes adding keywords to your photos fun.

Highly recommended if you have a lot of photos. Two things impressed me in particular:

1) If you change your keyword structure the keywords already assigned to your photos change to reflect the new structure.

2) The ability to copy and paste keywords from one photo to another. Big timesaver.

I only gave the program a 4 for features because I can see some logical areas for it to gain more abilities.

For example, it could offer the ability to embed your keywords into the photos themselves (I don't think iPhoto does that currently).

But overall this program gets a 5 star rating from me.  
(Version 1.2)

JOKKE  This little plugin enhances iPhoto keyword management invaluably! Not only does it make keywords usable in iPhoto but it does so in a way so reminiscent of the Apple way, that you soon forget it was not always part of iPhoto. And it should be.  
(Version 1.2)

QUBEX  Though I've always been a heavy iPhoto user, and I've always been aware that Keywords are the key to a flexible user experience, I'd always found the default Apple keyword-managing interface to be so clunky as to be basically unusable.

Keyword Manager is a godsend. It's a fantastic piece of software that does exactly what it advertises in the best way possible: easy assignment and visualisation, simple searches and hierarchical arrangement of tags all in a simple, elegant, unobtrusive interface.

It's simply wonderful. I recommend it wholeheartedly.   
(Version 1.2)

JIMW  I have not used Keyword Manager but have read the specs noticed the concerns about the price. For those who price is an obstacle there is a lighter duty product call Keyword Manager that has some of the basic features of this product. It is Keyword Assistant. Its price - free. I have been using it for years with no problem, Granted this is a more full featured product but if the price is an issue you have an alternative that might suit your needs.   
(Version 1.2)

BEN FOX  To say it with one word: awesome. Keyword Manager is just what I needed to organize all the drawings from my free comic site http://www.geek-happens.com/. You have full control on categories and keywords and also can easily rename them. For retrieving your pictures you can either use Keyword Manager's filter function or the built-in spotlight search. Honestly guys, I'd have even bought this plugin for 50 bucks. €19 is a real bargain and with the promo-code somebody mentioned below everybody who uses iPhoto and does not buy it is just crazy. Thank you to Bullstorm!  
(Version 1.0.2)

HARRISTYPE  To me, this was a life saver. With over 5,000 photo in my iPhoto library, I had used the free Keyword Assistant to keyword most of the library, but it still didn't seem efficient enough. To those that haven't tried Keyword Manager yet because they were afraid of the $19 price tag, buy it at the developer's $12 promo price. After an hour or so, you'd probably agree that it was worth $19 or more if you have a sizeable iPhoto Library. With Keyword Manager, I keyworded nearly 500 photos in less than 15 minutes. I truly could not use iPhoto without it now.  
(Version 1.0.2)

GETSOMESAUCE  Hey - I saw this comment from the developer at Versiontracker.com and thought you mind find it interesting. Here is his exact post:

A lot of people seem to think that price of this plug-in is high. I can understand that to some people think that $19 is a lot of money. Some may not consider getting their photos organized be worth $19, or they have plenty of time to spend on keywording using iPhoto, or another tool. In any case, we're willing to try experimenting with the price. Until the 14th of December you can purchase Keyword Manager for $12, using the following promo code:

VT-542U845 (for people outside the EU: $12)

VT-542E845 (if you're in the EU: €12)

If we see that the number of purchases increase enough to make up for the lower price, we'll lower the price of Keyword Manager permanently.

As for you who are comparing the price of Keyword Manager with the price of iLife, please keep in mind that iLife is designed to sell Apple computers, and the development cost is basically part of every Mac you buy. We can't compete with that, so the comparison isn't really fair. Also, giving the plug-in a poor rating on say stability (you know who you are) because you don't agree with the price is also not fair, in my opinion.

Johan Lindström - Bullstorm  
(Version 1.0.1)

MDAMLI  Nice feature. Very well done and Apple-esque.

I would concider purchasing if I didn't already have Aperture, where you can import the iPoto Library and assign keywords more or less just as easily.

But for those who doesn't have or want to buy Aperture, this is defiitively one to go for.  
(Version 1.0.1)

ANDREW SCOTT  This is a sophisticated addition to keyword application in iPhoto. I use a lot of keywords partly because I have a large library and use Flickr, and therefore tagging, extensively. I like the way Keyword Manager applies multiple keywords when you apply a keyword that is a subcategory. Removing a keyword is also much easier than it is in iPhoto.

It could be improved by the ability to alphabetise keywords. Also the price, for me, is too high, especially considering the Keyword Assistant is free. For $10 I'd be converted but for now I think I'll have to stick to KA.

Nice work though. A mature expansion of keywords in iPhoto.  
(Version 1.0)

GRYPHONENT  $19??? Be serious... at $10 I’d purchase without a second thought. What do developers think when they put out software that is a one-trick pony and charge prices that are way out of line. iWorks goes for $79... and iLife, including iPhoto, costs some $99.  
(Version 1.0)

SLNEW  This is brilliant, and I really like the way how I can activate it by clicking iPhoto's keyword button. Also being able to manage keywords in categories, instant search keyword.

I say job well done.  
(Version 1.0)

JOOLS912  This looks very nice. The design of the windows fits perfectly with iPhoto's in-built palettes etc.

Functionally its very good too. Exactly how I would expect this feature built-in from Apple to work...

But $19.00? Half that and I would purchase this without thinking, and I'm sure the developer would get more registrations as a result.

But for now, I'll stick with Ken Ferry's slightly inferior (but infinitely free-er) Keyword Assistant:

http://www.macupdate.com/info.php/id/14092  
(Version 1.0)