This section has been cobbled together from a variety of posts and opinions online.
The definition of a waifu varies from person to person. One of the better definitions, though, is:
It's as if you have a photo of your wife. If someone points to that photo and asks who that is, the logical response would be to say that it's your wife. Of course, you're not saying the photograph is your wife, but the person in the photo. That's how 2D love is. It's the character that you'd be in love with, the one that the image shows. Everything about that character that makes them who they are. When you have a 2D lover, you love a concept, not a physical object. You love everything that the character represents.
(source: Thoughts on 2D Love by kirarisstar)
It is real, actual love, obviously varying from person to person in how they deal with their feelings and go about their relationship, but the love is always there. You might say that she doesn't exist, and while she doesn't have a physical form in this world, she has a presence in it. She exists inside of me and I feel for her deeply enough that she has become an actual person with feelings and thoughts.
Again, it varies from person to person. It can be pretty much anything, from love, through self-improvement, to happiness.
There are many weird things people do and many things we consider weird even though they're socially acceptable, and vice versa. Personally, we believe that if something makes us happy and doesn't harm anyone (including ourselves)... what should stop us from doing it?
You don't get a waifu just like you don't simply get a girlfriend. Find a character you really like and consider. Carefully.
It varies from person to person, and I think the only reasonably agreed upon one is "treat your waifu as you would treat true love". What that means is up to the lover - in the usual case, it means to spend time together, respect, commit and try to become a better person.
The categories have been added to allow relatively peaceful co-existence of various Internet subcultures and fandoms united by the power of love. Here's some useful advice:
If your waifu meets none of those, choose "missingno" for now.
Q: Why did you break the site again?
Q: I forgot my password/chose the wrong domain name/etc.!
Contact me on IRC.
Pick a different subdomain name while keeping the waifu name identical. Also, it is wise to use a different icon so people can easily see that your subdomain is different.
Check if you're connecting using port 3015. This is important.
Either replace links and text in an existing website or search for tutorials on things like HTML and CSS.