I made reservations for apartments in Paris, Rome and Venice through WorldBy.Com (aka ParisBy or ItalyBy) but have concerns that the reservations may not be honored when we arrive in March. I have received extensive confirmation e-mails from each reservation, but can't seem to find out how to contact them for re-confirming. The e-mails sent always have the "don't reply to this message" statement.
Any help or experience would be greatly appreciated.

Without knowing more specifics as to which properties you're dealing with, all I can suggest is to go back to the web pages and look closer for email addresses other than the booking form email.

Hi Dan.

Can't you contact worldby.com directly and ask them for the contact information for the owners?

Dear AtlantaDaniel

I am writing to you from WorldBy.Com regarding your concerns expressed here in the forum on the reliability of WorldBy.Com.

I would like to assure you of the absolute reliability of WorldBy.Com.

I urge you to read your reservation vouchers carefully. You will see that in each the telephone number, fax and email address of the hotel is provided and you can reconfirm your reservation using any of these methods. This is a practice that WorldBy.Com has always followed. Every voucher that is issued contains full contact details of the hotel.

The email messages that contain the "do not reply" message are simple notification emails to confirm you have completed an action. The emails always contain a link that you can use if you wish to respond (rather than using reply).

Please do not hesitate to contact me if you would like us to follow up any aspect of your reservation.

Kind regards
Andrea Brown
WorldBy.Com

PS,

If you do a text search for italyby.com you will find postings from folks who have used this agent.

You might wish to ask them about their experiences.