Examples:

++	--	Total vote	tension
100	5	95	low
10	5	5	low
5	100	-95	low
5	5	0	low
100	100	0	high
20	20	0	medium
50	20	30	medium-high

Another phrase for "tension" would be "high interest, controversial".

Matt

Update: grammar, clarity tweaks

#!/usr/bin/perl

use strict;

my $plus = shift;
my $minus = shift;
my $sum = $plus + $minus;
my $rep = $plus - $minus;
my $mean = $rep / $sum;

#ALERT: semi-empirical formulae ahead
my $tension = (1 - $mean ** 2) * $sum * 2 / (2 - 1 / (1 + abs $rep));

$tension = log (1 + $tension) - 2;

my $literal;

for ($tension) {
    $_ <= 0 and $literal = 'no', last;
    $_ <= 1 and $literal = 'low', last;
    $_ <= 2 and $literal = 'medium', last;
    $literal = 'high';
}

printf <<"EOF", $plus, $minus, $rep, $tension, $literal;
Plus       = %3d
Minus      = %3d
Reputation = %3d
Tension    = %.3f
There is %s tension on this post.
EOF
[download]

$|=$_="1g2i1u1l2i4e2n0k",map{print"\7",chop;select$,,$,,$,,$_/7}m{..}g