Update II

we've added even more features to enhance SERPs read about the update with things like personal search status and Insights for search integrated into Webmaster Tools and SERPs of the major 3 search engines

Update

Well thats funny... @merrillg pointed out this is the data from the anchor text tab in the links section... makes sense its there considering it is anchor text but it shows in the keywords feed and not the keywords section which is where i got confused... I was wrong about it not being published anywhere else but this data is still pretty important... I cant believe I didn't notice that tab before... I guess I was distracted by the link data... sorry :(

Original

The keyword data that Google Webmaster Tools shows you is only part of the data that exists for your site... its up to 200 internal keywords, this comes from your pages and you can manipulate it based on the keywords you use in your content. But thats not whole story, what about that all important anchor text? Now of course you could go look at Open Site Explorer but wouldn't it be great to see what Google sees as your anchor text? I found the other keywords, the external keyword data hiding in a little known feed in webmaster tools... now aside from this guy who sounds a little like a consparicy nut and a short mention in the feed documentation nobody is talking about this data... Unfortunately i couldn't get pass through authentication so you have to put in your password but thanks to my new extension SEO Site Tools for Google Chrome you can navigate this data all from the safety of your favorite browser :)

heres how easy it is to get the data... open the tool from the Page Terms / Tools section

put in your login and it will present you a list of sites associated with that email addresses Google Webmaster Tools... choose one and you will see something like this
it will show you up to 100 external keywords... but what is this data that is published nowhere else any why is it so valuable? well lets take a look at bit of the list from my blog...

carter cole
carter cole developer
http blog cartercole com 2009 10 awesome syntax
16.52 del icio us easily embed tweets in
syntax
this feed is from my technology blog
embedding your google profile social icons
my technology blog
http blog cartercole com 2009
some code for asp and php

you know how sometimes when you do a search and look at Google's cache and see that "These terms only appear in links pointing to this page" thats what this keyword data is... its the external keywords Google has associated with your site... when I searched for some of the unique ones like "this feed is from my technology blog"
my site was the first result... i append that text with a link back to my site at the end of my rss feed so if someone republishes my content i can get credit for creating it... so the scrapers are sending that anchor text back to my site and whats even more interesting is that some of these keywords are from links that are no-followed so it might be that those links while not passing juice are passing something possibly even more valuable... their anchor text

the tool is still super beta and has some errors so please send me feedback to the email provided in the tool with any ideas/thoughts you may have about this very interesting data feed thats hiding in the webmaster tools data feed

again you need SEO Site Tools to get to this data and aside from doing some HTTP Gets yourself i know of no other tool that shows users this data

Update

i found some screen shots of the old tool on SearchEngineLand before it was removed