This looks to me like it's just a wild rumour, but I thought I'd pass it 
along just in case anyone else has heard anything.

From John Chismar:

" . . .I was out to lunch today with some traders and one of them questioned 
whether or not Platt's had contacted us yet.  His comment was that Platts was 
preparing to launch an offensive against all E trade systems that use Platt's 
as a settlement.  They want to claim a royalty or commision for each deal 
transacted.   Must be something to it as he claims there is a precedent - 
Platt's is owned by Mcgraw Hill and they publish the S & P index and 
supposedly  won a lawsuit for all trades done vs that Index.   Just thought I 
would pass this on to you as not sure if you were aware about this or if we 
had already had legal opinions about it. "