When the Dolphin is going to really work, is there going to be a possibility for consumers to use some kind of trial version, so he or she would have an idea of how the web site works?
There will be no trial versions directly, I'm afraid. It is made so intentionally, because otherwise a Sybil Attack would be immediately possible with next to no cost. However, there is a mechanism that allows investors to return funds spent on DoBI, at least, during the first year (read more about that in Section 4.2 of whitepaper).
In the end, we could make a special demo separated from the main platform's economy, if it's what the community would really want.