Hello Philip,
Google doesn't like that ...
This is a myth. Google does not mind about it.
Google tried to kill off the myths around duplicate content years ago. Susan Moska posted on the Google Webmaster blog in 2008: Let's put this to bed once and for all, folks: There's no such thing as a “duplicate content penalty.”
Check the
article from 2008 on Demystifying duplicate content penalty
for more information.
As you'll read in the Google documents, duplicate content won't harm your ranking in the case of iCagenda events. The Joomla CMS itself generates duplicate content for articles if several menu links point to the same article.
When an iCagenda event has multiple dates, it deliberately generates a date attribute at the end of the url, to enable a permanent link to the precise date.
If you want to define a canonical URL, you can use an extension dedicated to managing canonical urls.
A canonical url is only useful if you want to define a single url for the same element.
In this case, Google will only reference the url you've defined as canonical.
You can find out more about canonical urls here:
support.google.com/webmasters/answer/66359?hl=en
It's not possible (or a good idea) to add a function to set the canonical URL automatically for you in iCagenda, as it all depends on the parameters of your menu items and what you want the result to be.
It's better not to define a canonical URL than to define the wrong one.
Hope this gives you insight on duplicate content?
Best regards,
Cyril
