BTW, this question has been asked twice in the Google Group without an answer, in 2008
and 2010:

https://groups.google.com/d/topic/selenium-users/mEhu4SKPAUQ/discussion
https://groups.google.com/d/topic/selenium-users/3uyurUr5EXc/discussion

I know this is no pretty in any case, but I've discovered a workaround to get Seelenium
to work properly with URLs with hashtags (at least for me it seems to work):

mDriver.Navigate().GoToUrl(url);
mDriver.Url = url;
mDriver.Navigate().Refresh();
mDriver.Navigate().GoToUrl(url);

Hope this helps

We also encounter this problem, we are using Selenium IDE and the open command with
a new URL reports a timeout error. 

This is very problematic for us because our app is a RIA one and without any command
to only change the URL hash we have to write lot of commands to reproduce the user
path which is equivalent to a simple hash change. 

Is their somebody who knows a trick to perform a hash change using Selenium IDE ? It
would be great to have a 'changeHash' command in Selenium for this purpose.

Thanks.

As a temp fix we just set the hash in JS

// PHP
protected function navigateHash($hash_url) {

  $this->getEval("window.location = window.location.href.split('#')[0] + '#/' + '$hash_url';");
}

FYI, our team stopped using Selenium IDE, and we use the Python Selenium WebDriver with
Behave to write our tests.

Ok, thanks to you responses I finally found a solution. 

In selenium IDE simply use the 'storeEval' command, for example : 
 Command = storeEval
 Target = window.location.hash='events/5000/participants/7011'

Selenium RC is deprecated and the support of Selenium RC is discontinued.

Selenium team is not going to fix remaining issues in Selenium RC and we don't accept
new issue reports on Selenium RC.

On the other side, we continue to accept pull requests and patches from the community.