Do I HAVE to go through Hubzu if I want a property?

[Brandy Vee]

Sorry for my ignorance, but I have never heard of Hubzu until now. I am interested in a REO property I found on Zillow, it says its for Sale and the listing was "brought to you by Hubzu", listing provided by So-in-So (name omitted) Realty. Now, when I go to the property's listing page on Hubzu, it says "Highest and Best Period Ended, you can still watch this property". Does this mean I cannot submit an offer for this listing? Or can I still call up the listing agent and submit an offer the traditional way? Common sense would tell me Hubzu is just a modern tool to submit an offer, and that I can still submit an offer the traditional way through the listing agent. However, the way some people talk about Hubzu listings makes me assume you HAVE to go through Hubzu if you want the property. Can someone clarify? Thanks.