Because not all of them make the front page? And even if it did, this person probably missed it. Really, is that so wrong?

Sorry! I follow HN primarily through the RSS feed and a lot of posts/threads never show up there.

Before posting, I did Google for polls on the subject of version control and didn't turn up anything (oddly enough, this thread seems to be at the top of the results page):

http://www.google.com/search?hl=en&q="version+control"+poll+site:news.ycombinator.com

Even if I had seen your poll, though, I probably would have posted anyway because I'm interested in getting a feel for how many people use some of the systems that are listed at top besides Git, Mercurial, and Subversion.

Also, that poll had much fewer choices.

For that matter, this one doesn't have plain old RCS, which is what I use.