This one really slipped past me, I guess because I fancy Google a whole lot more than Yahoo, but Yahooties(sorry, Yahooligans is already reserved for kids so…yeah) deserve their toolbar too. And they've got it! The Yahoo Toolbar(previously Yahoo Companion) came out of beta sometime late July.
Nothing really special, all the basic Yahoo style features: Mail stuff, Games, Personals, Music, Finance. I don't know what your take on it is, but I don't really like it when a service, by default, tries to offer me a whole bunch of stuff I'll probably never use. I guess it's just Yahoo's style that pushes me more toward Google, which generally gives you the basic stuff that most people will find useful, and lets you customize. Hmm…Not sure exactly what it is, haha, I just don't get a good vibe with Yahoo. It just seems like I'm dealing with the devil or, even worse, Microsoft. 
Like I mentioned, though, Google's toolbar has features that everyone can find useful. Of course, a search box is built into Firefox, but the Google Toolbar lets you immediately choose what type of search to perform(Image, News, or search inside the site you're viewing). And a built-in Spell-Checker is always there to keep you from embarrassing yourself on your favorite forum(I just used it in writing this article ). There's AutoFill, to remember form information, and AutoLink to automatically turn addresses on a page into a link to Google Maps. And a really exclusive feature, PageRank, that gives you a rating(0 through 10) of every page you visit, and is often helpful in deciding how important and credible the information you're looking at really is. Apart from all that, there are a bunch of tools to aid in searching.
One of my favorite parts of the Google Toolbar is that you can put any of it's buttons on any toolbar in Firefox. Put the PageRank meter beside the address bar, if you want, or the Options button near the menu bar! It's a really cool extension! 
Here's how:
- Go to View > Toolbars > Customize.
- Add, move, or remove any of the buttons(including Google Toolbar ones) you want, by dragging and dropping.
Yahoo Toolbar won't let you do this, to change it's buttons you have to sign in and edit them from a web page(you've got to sign in with your Yahoo account to use any of the features)…tedious, especially compared to Google Toolbar, which only opens a small pop-up when it needs to load a web page(for help and other stuff), so you don't have to take up a whole tab for it.
So my evaluation is that, while Google Toolbar has less features that have to do with online dating services, and checking up on the latest Basketball scoreboards (oh wow! lol), it has features that most users will actually find helpful, and you don't need a Google account to use any of them.
Hey you! Yeah, the one reading this. Post a comment if you've got an opinion, or some feedback! I don't want to be alone here, honestly, so make something up if you have to! Just kidding, but really, don't be shy, and drop a line if this article, or any others, interest you. Thanks for reading!
Zac M