Could someone explain power factor for me please (and I guess a few others)
?

The reason being is that I have a lot of CFLs and so the rated power
consumption is somewhat less than if these were ordinary filament bulbs.

However the other day I plugged in a few to my gizmo that tells power being
drawn in watts and also power factor.

The power factor was around 60% on the CFLs.

I believe the elec company doesn't like devices with a poor (low?) power
factor but I don't know why.

The other concern is how does the electricity meter measure power drawn by a
device with a low power factor ? - does it over or under read ? Also does
this vary between the older eddy current spinning discs and the newer
flashing LED meters with some other method of measuring power.

Basically my elec bill is still way higher than I think it should be and I
am trying to get to the bottom of it.

Thanks,

Nick