Can someone tell me what this is in WP 2.9?

# We now have rel=canonical support for better SEO.
# There is automatic database optimization support, which you can enable in your wp-config.php file by adding define('WP_ALLOW_REPAIR', true)

Do i have to do anything ?

 

nopes.. you need not do anything... just upgrade your database once.. then just sit back and enjoy..!!

 

I couldn't have said it better

 

what is canonical support for better SEO.

 

It automatically includes the rel canonical tag in the header of your html. The tag will be populated with your permalink. This tells search engines the proper URL, just in case they come across variations, such as example.com/post-name/comment-submitted?mode=true
(just an example - some plugins might generate urls such as these)

In this case, the tag would look somthing like this:

<link rel="canonical" href="hxxp://www.example.com/post-name" />

hxxp://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html

So you don't have to do anything..

 

The most exciting addition that i found out is the ability to edit images from within your browser using the new basic image editor.

Now we can rotate, crop and flip. It's really make the image editing become easier. Dont need to edit using image editor before post it.