It's not very standard. The standard text in a UGC site's terms is to grant a non-exclusive license to the submitted content, and does not grant the sole rights to enforce the copyright in that content. This text on the submission form is both new and non-standard; it doesn't even agree with what's in their TOS document.
An exclusive license means landlords themselves are giving up their right to post the same listing on other rental listing sites, for example, by using a tool that would post the exact same listing to multiple sites.
