... continued from yesterday.
John was baptizing people, dipping Jews in the river Jordan to symbolize the washing of their sins. I would have heard the message: we Jews need to prepare ourselves for what is coming. We need to clean ourselves to be ready or else we'll be swept up in the judgment along with everyone else.
Such ritual washings were of course a normal part of Jewish life. There were miqvaot around Jerusalem, for example at the temple. You purified yourself before offering sacrifices. The Essenes at the Dead Sea had a miqveh at each entrance to their camp. You walked down one side unclean and came up the other clean. If I had seen John as an onlooker, I probably would have pegged him to be an Essene of some sort.
What was different about John's baptism is that he wasn't dipping people as usual. His baptism wasn't something you did each year or each month. This was a preparation for a one time event, the coming judgment of God on the world in preparation for the restoration of Israel, God's coming kingdom.
Part of that message was a new king, a new "Son of David" to resume ruling Israel just like the kings of old. This "anointed one" or messiah (Christ in Greek) was an intimate part of the restored kingdom. It may take a little doing to get into the heads of the people alongside the Jordan and what they were expecting in a messiah because not everyone was.
First, the people by the river were not expecting the messiah to be divine in the normal sense of that word. True, there were Old Testament texts that referred to kings like Solomon as the "Son of God" (2 Sam. 7:14) and other texts that used very exalted language of the kings of Judah on various occasions (e.g., Ps. 2:7; 45:6-7; 89:27; 110:1). But no one took these verses to mean that the king was literally a god or that the messiah would be a god. They took it poetically.
It was perhaps the Essenes who first starting expecting God to anoint some special people in the process of restoring Israel. Some of their key documents look forward to two "messiahs," two anointed ones. One would be the new king of Israel. The other would be the new priest of Israel. But the group called the Sadducees weren't necessarily looking for a new king. For them, Israel had done just fine with the high priest basically in charge for five hundred years.
As for the rest of Israel, from time to time revolutionaries would crop up, probably with hopes of turning out to be the new "anointed one" of Israel. Acts mentions some of them.  A book called Psalms of Solomon, especially chapter 17, very strongly hopes for a messiah to come and destroy the Romans.  But we really can't say how prevalent the expectation of a messiah was at the time John baptized. Obviously he believed that a king was coming.
And here it is important to recognize that the Jews at the time of Jesus largely didn't read the verses of prophecy you might have learned in Sunday School the way we do. The New Testament authors, by and large, read the Old Testament "spiritually" rather than for what the words originally meant. It was only after the fact that Christians saw most of these Old Testament verses the way we do now. In other words, it was not at all obvious to everyone either that a messiah was coming and certainly not that he would come in the way Christians now believe Jesus did...
 E.g., Acts 5:36-37; 21:38.
 It was written not long after the Romans defiled the temple and took over Israel in 63BC.