Yes, multiple people are able to place a backorder on the same domain name. Though, this wasn’t always the case. Only since about 2009 have multiple backorders been able to be placed on a single domain. So, even if a domain backorder has already been placed on a domain name that you want, you are still able to place your own backorder on that same domain name. What happens though with domains that have multiple backorders placed on it is that the domain will go into auction when it becomes available again for registration. The auction will be among all of the people who had previously placed a backorder on the domain name.