S3D paypal?

["Dr. George A. Themelis" <drt-3d@xxxxxxx>]

The latest trend in internet auctions is paypal, a free
service that allows the buyer to charge items in his credit
card.  Details are here:

www.paypal.com

I asked, how can this service be free, considering that
a credit card company charges 3% for each transaction?
I was told that they will make the difference through
interest accumulating in open accounts.

This does not add up.  My suspicion is that the charge
will appear as a "cash advance" instead of a regular
credit card charge.  This means that the credit card
holder will be charged (by his credit card company)
a fee, plus interest will start right away.  Even if this
is the case, it still might be an attractive service for
some buyers (not myself.)

Has anyone here seen charges from paypal and can
verify or deny my suspicion?  It is possible that initial
charges appear as credit card charges to lure people
into using this service and then they will switch to
cash advance charges.

George Themelis