It really wasn't unique at all. One of the best sources to see this playing out is in the works of Josephus. In the Antiquities of the Jews, Josephus mentions a number of other teachers or so called Messiahs (for Josephus, the emperor Vespasian was the Messiah). One of my favorite that he mentions was simply named the Egyptian (in the Book of Acts, Paul is said to be mistaken for this individual). Josephus tells us that the Egyptian had gathered a massive following, virtually a small army, and descended on Jerusalem. His followers were decimated though.

Josephus mentions numerous such leaders who had either large followings, or had more of an inner core of disciples.

Interestingly, there are a number of scholars who believe that Jesus was once a disciple of John the Baptist's, and it was that interaction that Jesus also replicated. E.P. Sanders, in Jesus and Judaism, probably gives the classical argument for this (Sanders has been a massive influence when it comes to 1st century Judaism). The basic argument is that Jesus sought out John, and by being baptized by John, submitted to John and his teaching. The idea is that Jesus would not have done this if he didn't want to follow the teachings of John. The Gospels also give some suggestion that Jesus took some of the followers of John as well, and that there was some sort of close connection between the two.

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So it really wasn't that unique what Jesus did and as Sanders argues, he may have just been replicating the sort of relationship he had with John the Baptist.