Yesterday, we reported on Google Sidewiki which allows anyone to basically comment on your site, on your site, with the Google Toolbar. Some webmasters are not into this idea and they want to know if there is a way to opt out of this feature. The answer is no, not an official way to opt out, but you can block these users completely.
One Webmaster in Google Webmaster Help explained that you can use a rewrite rule to block people with this toolbar.
Until Google dumps this or provides an opt out, web site owners who'd like to retain control of what appears on their own site can block all Google Toolbar users by adding the following to their htaccess file. The "notoolbar.php" points to a file explaining Google's bad behavior and instructing the visitor to uninstall Google Toolbar in order to proceed. You can create your own file and name it whatever you like, just be sure to change the code below to make it match the file name you've chosen.Update: See the comments below about this rewrite code.
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} GTB [NC]
RewriteRule .* notoolbar.php [L]
Of course, this would block anyone who has the Google Toolbar from getting to your site. Up to you.
Forum discussion at Google Webmaster Help.
Update: I have a new post on how to just block Sidewiki without blocking Google Toolbar users.
