Email doesn't exist outside of The Big Three?
Something that's always bothered me about email isn't how it works, but the fact people have such a difficult time remembering your address if it doesn't end with a specific name. If you have your own web site, you naturally want to take advantage of having your own email address using your site name. But will people remember an address with your site name in it? Nope.
The Big Three when it comes to email are addresses ending in @yahoo.com, @hotmail.com and @gmail.com. If it ends with anything else, it's pretty much guaranteed nobody will remember it at all.
Familiarity = Trust?
For whatever reason, people feel more comfortable sending a mail to Big-Three address compared to others. They see the names they know and feel safer about sending messages to them solely based on familiarity and nothing more.
Anyone who's technically inclined about email however knows that Big-Three addresses are no safer than ones that are not. Almost all email to this day is sent and received completely unencrypted. That's the way it's always been and probably isn't going to change any time soon, if ever.
Using a Big-Three address is better for.. everything?
I plan on having some business cards printed up fairly soon, and I'm going to list my Y! Mail address instead of the domain one. The people I give the cards to will see that and will probably be the only thing they remember other than my name. Will they remember the web site listed on the card? Of course not. But they will remember the email address. For small-biz people, yes, I strongly recommend using a Big-Three email address.
For personal use, same deal. Yeah, it's all cool and whatnot when you have your own web site, but to keep the communication flowing with friends and relatives, all they know are Big-Three addresses, so be sure to use one. And if you want maximum memory retention for the folks you give your email address to, make it a Y! Mail or Hotmail because those have been around the longest, because oddly enough, there are many people that have never heard of Gmail. Strange but true.