I think the roughly 5 votes per voter probably has more to do with Dextra's original voting instructions.
Perhaps a more telling measure in this case is to look at changes in voting behavior over time. Since the results of the poll are not blinded, one would expect the pattern of votes to shift as people take the previous votes into account.
In particular, one might expect to see a gradual decrease in the average number of votes per voter over time, as people see that fewer of their votes will actually "matter" (becaus ethe top places are already more or less locked in). One would also expect to see a shift from voting for the top candidates to voting for the second-tier ones (i.e. those around rank 5, where new votes may still create a change in the outcome) and lower (protest votes, and people using up their 5 "alloted" votes to indicate preferences below the 4-5 candidates who "will win anayway").
So what do we actually see in the data? Looking at the voting patterns at 190 votes, 408 and 614 votes (i.e. roughly 1st, 3nd and 3rd block of 200 votes) we see that...
1) the number of votes per voter has stayed approximately constant: 4.27 vs 4.11 vs 4.39
2) out of the top 5 candidates, only *one* has shown a significant decrease in votes over time, and that's JoeGKushner.
3) in the "second-tier" candidates, i.e A-M G, Xath and diaglo, there has only been a slight uptick in votes over time,
4) the lower tier of candidates hasn't really seen a very significant increase in votes over time either.
Overall, the voting patterns haven't really changed much over time, despite what one might expect for such an open poll. So in that sense, I don't really see any evidence of strategic voting either.
(PS: before anyone hammers me for this, I used "significant" in the colloquial sense here. If I had more detailed voting data, I could randomize vote order and put some actual p-values on there, but I'm not *that* much of a geek that I'm going to do real statistics on a beautiful Saturday morning.

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