|This page in a nutshell: Appreciate all your fellow editors while you can.|
On Wikipedia, and online communities in general, it is almost inevitable that you will make online friends with other users. Users that you make friends with tend to be similar – such as both being newbies, similar interests, or perhaps friends as respect. These users, often who live thousands of miles from you, and who you'd likely never ever meet become your online friends, and a great part of your online life, and even though you don't know them, they are often as good as friends in real life.
Sometimes though, people do not always manage to have internet access. On Wikipedia, a user may put up a wikibreak notice indicating this, or tell their closest online friends. What is unfortunate though, is when a user "forgets" to put up one of these notices, their edits will cease, and in effect the user will simply disappear. In real life, it is normally possible to know of friends' whereabouts because you know where they live, their phone number, people who know them etc. But online, what can we assume? A very prolific editor suddenly grinds to a halt one day, and never edits again, with no explanation or possible reason why this should be. It is even worse when the user no longer replies to emails. What on earth happened, we ask. Did they grow tired of Wikipedia, and just decided to give it up one day? Or is it something more tragic, and that the user couldn't return...?
What should be done is, whilst you're on Wikipedia, treat everyone with courtesy, and don't hesitate to tell someone they did a good job. There are too many editors on WP:MIA that are sorely missed by many users, who perhaps wish they'd spent more time getting to know them and paying them more kindness that they deserved.