Father, Son and Holy Spirit are three separate entities. But they all have the same personality. And that personality is to be identified as God.
The difference between the three is not in their personality, but in their circumstance. The Father is what someone like God would be like if they had the powers of... well... a God. The Son is what someone like God would be like if they were a human being. The Holy Spirit is what someone like God would be like if they were a community.
A couple of sub-questions to help think about this:
Is this idea compatible with the idea, in the abstract (i.e. divorced from particular verses from the Bible or whatever), that there might be "Three persons with one essence?" In other words, would the idea I just articulated be a good example of the kind of strange logical construction some Christians and most non-Christians have a serious problem with when considering the possibility of something like the Trinity?
Is it possible to understand the OT God and the NT Christ as having "the same personality?"
How incredibly unorthodox is it to assimilate the notion of the Holy Spirit to the notion of the "spirit" (so to speak) of a community of people?