Until now, you had to verify you owned every sub-domain on a domain before you could use webmaster tools for it, while for most sites this is fine, you verify the www. version, sometimes there are a couple more that need to be done.
for example on my site, I use the non-www domain, also there is a dev. and a api. that also need their own verification meta tag/html file. If I want to use webmaster tools on another sub-domain I have to verify again… this becomes a tiresome process.

Enter the new DNS verification. You now add a TXT record to your dns and it automatically covers any sub-domains you add.
That’s it… done! There is of course the usual dns propagation you have to worry about so it may not be a quick as adding a meta tag, but it defiantly saves time in the long run.

You can find out more by visiting the Google Web master tools or popping over to the Webmaster Central blog.

What is the Google Webmaster Central Channel?
Its a channel on Youtube that is used mainly by Matt Cutts (project leader of Googles web spam team) to pass on little snippets of info and answer questions made by Joe Public and his wife on the Google Forum. It is also used by other teams,  to give useful information and advise on how to make the most out of Google and the web as a whole.

Why should I watch them?
Why not? Google are market leaders in their field and they are giving advise (for free) on how to improve your website, I’ve learnt many tips and tricks from watching the videos and a lot of them have helped out a lot.

Where can I watch the videos?
Here is the answer, on YouTube – http://www.youtube.com/user/GoogleWebmasterHelp

The first is called ‘Fetch as Googlebot’ as allows you to view the information that Googlebot retrieves when it visits ont of the pages on your site. This is what people, webmasters and SEO ‘experts’, are most likley to be interested in. At fist glance it appears to be just the source code of a page, and while yes it is, it does also contain the server headers that were detected, so you can use the two to determin if googlebot sees your page as you want it to.

The second feature is a Malware status page, this feature has been around for a while outside the webmaster tools, if you knew where to find it, and its a useful tool is your site does contain some dodgy code, its good to see this is now part of the webmaster tools and easier to find.
There is a good post on the Google Security Blog that can tell you more about Malware detection so rather than write about it myself, I’ll refer you to it.