I've known Elise from alt.polyamory as an interesting person on the internet for years and have spent small amounts of time in person with her, at alt.polycons and once, memorably, for a visit to the temporary Chihuly exhibition at the V&A in London. Mike wasn't able to travel much - at first, because of kidney dialysis, then because as a transplant patient he had a suppressed immune system. So I knew Mike only through his writing - when you're a Neil Gaiman fangirl and Neil Gaiman tells you check out his friend's work, you do it. I'm not as well-read as many of my friends (mainly because depression stopped me being able to read anything longer than a short story for many years), but I know when someone is talented and special.
by Neil Gaiman
"The Declaration" by John M. Ford, and "Response [...]" by Elise Matthesen - you can leave condolences for Elise here
by Jo Walton, a.k.a. papersky
There are worse places to spend eternity.
xiphias once again finds the right things to say.
[*] There is a convention on the rec.arts.sf.* groups that, if an article is posted that just has someone's name as the title, it means that something bad has happened to them. I've never been on any of the rec.arts.sf. groups, but I was on alt.poly which has a lot of crossover for years, and absorbed it. Even now if I see a livejournal post that's just someone's name I'll start to panic until I've read it.