The rally might be coming to an end, or it might be an opportunity.If you hadn't heard of Opendoor Technologies (OPEN -2.68%) before June, chances are you've heard of it since. Opendoor stock has had an unparalleled rally over the past few months, fueled by retail investor power and the strength of social media.Opendoor stock gained nearly 2,000% from its low in June through its year-to-date high in September, but it's been starting to fall since then. Is now a good entry point? Unlocking the digital real e ...