User blog comment:AYET/Progress of SHP's respective dreams/@comment-4899461-20121029141335

Joy Boy lived in the void century. And personally, I believe that he was one of the key figures of that time if he was able to socialize with the Mermaid Princess. So gaining the knowledge of him would actually be a big step forward for her.

In the realm of pure speculation, I would imagine that the Revolutionaries would have taken her to some Ponneglyphs during the timeskip in order to maybe advance their own goals. Robin didn't go with the Revs. in order to get stronger in fights, I think she went with them more in the pursuit of knowledge and helping her dream. Since she hasn't been seen with any mentor or Okamas chasing her, her increase in power probably could have happened anywhere.