Trying to e-mail someone who isn't in your address book can be a pain--especially if your phone's auto-correct did a fantastic job replacing parts of the address with dictionary words.
You could send them a test message and see if you get a delivery failed e-mail in return, but this can be embarrassing because they'll most likely read it and wonder what's going on. Next time this happens to you, try using eToolz instead. eToolz contains, among other nifty things, a tool that can verify the validity of an e-mail address without notifying the person. To find out how this works, follow these five steps:
Step 1: Download eToolz.rar and extract it to a place you can find it easily.
Step 2: Run the eToolz program by clicking it from within the directory you extracted it to.
Step 3: The default language for the program is German. If that doesn't present a problem to you, cool. If it does (since you're reading this in English), open the Extras menu and mouse over Sprache/Language. Select English from the menu that appears.
Step 4: Click on the Mail-Check tab from the bar of tabs.
Step 5: Fill out the text box labeled E-mail address (the other information is completely optional). Click the Start button to begin the test. After a short while, the results of the test will be displayed in the text area (final results in green).
Unfortunately this tool can't identify who the confirmed e-mail belongs to, or magically conjure the last half of the e-mail that you're trying to remember. It does come in handy when you write an e-mail address by hand only to come to it later and realize you can't read your own handwriting. Give it a try and share your results.