When I got to know about Gmail, my first selection of username is obviously raymond@gmail.com but then the registration page reports that “Someone already has that username” so I had to choose another username. I was shocked to know that Google actually reserves the username Raymond because I just found out that the username is still not yet being taken! One logical way to test whether an email address is valid or not is by sending a test email to the recipient email address. If the email bounces back immediately, then it means that the email address is not valid while if you’re not getting anything in return after waiting for a few minutes, then the email address probably exist.
I tried sending a test email to raymond@gmail.com and within a couple of seconds I got a response from Mailer Daemon saying that “The email account that you tried to reach does not exist”. Even if I work for Google, I don’t think they will allow me to use the username raymond@gmail.com because they would require me to register my last name in the username. Anyway, other than sending a test email to check the email address validity, an alternative better method is to verify the email address at Email-Checker.com
There are a few other online services that offers email address verification but I find that Email-Checker.com is more accurate and superior when compared with its competitors. One good example is most online email checkers fails to check Yahoo email address validity because Yahoo servers always states that the checked email address is always a valid email address. However I’ve tested a couple of valid and invalid Yahoo email address at Email-Checker.com and somehow it is able to determine if the Yahoo email address is valid or not.
To verify an email address validity with Email-Checker.com, visit Email-Checker.com’s webpage located from the link at the end of this article, enter the email address that you want to check at the “Enter an email to try it” box and click the “verify” button. Within seconds you will get a popup with the result.

It is able to report if the email is:
Valid – email address passes all tests. Invalid – email address does not exist. Unknown – domain accepts all requests. Unknown – email is disposable email address (DEA). Unknown – email is grey listed – try again in 5 mins. Unknown – email cannot be verified (other reasons).
Checking a single email address at Email-Checker.com is always free but if you need to verify a list of email address in batches automatically, then they do offer a few paid packages to serve that purpose.

I’m using verify-email.org/ to check for valid emails. Works just fine with yahoo and all other email providers
Actually, if you were working for google, your pro email address would probably be raymond@google.com. Except there probably already exists another Raymond working for google !
really nice info, thank you!!
This website have became since few months an advertisement website.
All it has been doing recently is advertising third party products.
I miss the old days where Raymond was posting tutorial on very technical and advanced stuff.
Well after all every site has a moment where it starts to drop down..
It is unfortunate that you have such mindset and thinking.
I do not get paid at all for sharing a link of an online service, so that doesn’t count as advertisement.Secondly, there are software that can do this, but why need one when you can do it online without installing anything?
WTF are u saying??? why dont u yourself do this stuff???
total idiot