how to get a read receipt in Gmail, Yahoo, or Hotmail ?

people who are using exchange mail know that there is a important killer email feature delivery reports and read receipt in ms exchange mail with which you can easily know whether your email was opened or not.... recently one of my reader asked me whether there is any option to get read receipt/ delivery reports in gmail or any other free email services being an application developer and working on mobile platform on similar applications i know most of the free email service uses imap/pop protocols and they do support read request and delivery reports..

so why in the hell gmail, yahoo and other does not support these options in their webmail? the answer is i too dont know but these options works flawlessly if you configure your gmail l to outlook, outlookexpress, thunderbird or eudora desktop email clients havent tried with yahoo and hotmail as they require paid subscription to configure and access via desktop email clients..

so will i get read receipt if i configure my email account in outlook, thunderbird or any other desktop email client? again there is a catch here this option only work if the recieving end supports this feature or use email clients like yourself... if he/she is using webmail to open then you will not get read read reciept.

So is there any other way to know whether my mail has been read?
Yeah there are some third party service like spypig.com, readnotify.com etc where they give a small tracking graphic(html code or script) where you can embed it in your email once the recipient opens the mail you will instantly get email with information like ip address of recipient, time of opening and how many times and at what time he/she read your email..

yupee!! will this solve my problem do tracking stuff works?
Thought this method is extremely effective this trick does not work if the receiving end has blocked all the images or configured to receive the emails in plain text.

so bottom line is despite of all tricks there is no 100% guaranteed way to know whether your intended recipient has read your email or not so if your requirement of knowing this information is critical then it is better to use a exchange mail.. though this is based on best of my knowledge if you know any other tips, tricks or suggestion do let us know.