Yeah this looks like an interesting site.
The cfls in question are professional cfls and not the kind you get from your supermarket for a dollar.
I dont know if anyone else looked as i didnt read all 3 pages of this thread but it states the usefullness of the purple cfls for growing as well as the other colours so that growers that choose good cfls can buy the correct colour bulbs for the different sections and stages of their planrs grow areas.
Here is the link to that site again in case anyone wants it.
A very good site i think.
nlite cfl's
And here is their cfl colour usefullness chart that shows how to mix and match your cfls to achieve the best results.
Its worth remembering that pro grow cfls are much much better than shop bought rubbish