Shares of Opendoor Technologies have skyrocketed, but be careful what you read into that price advance.Opendoor Technologies (OPEN 14.13%) operates an interesting housing-related business. There are reasons to like the stock if you are an aggressive investor. But there are also some very big reasons to be cautious. Before you buy Opendoor Technologies thinking it will make you a millionaire, you'll want to dig a bit deeper into the company's story.What does Opendoor Technologies do?From a simple perspective ...