missing something?

Some popular races are on sale now (or will be shortly) and sell out many months in advance, so in some cases what you're seeing is people signing up for those so they don't risk getting shut out of them.

In other cases, you're just seeing people sort of "thinking aloud" about what they'd like to do next year...

The races that tend to sell out a long time in advance are typically IM or HIM events, but not always...the Malibu sprint tri here sold out in a couple hours when it went on sale last spring.  If you have your eye on a particular race or races, it's never a bad idea to ask around to find out if a sell out far in advance is possible.

Related question: Sign for my first race is not open till Mid December, yet the race site lists on person signed up already. Is this a re-schedule from last year or possibly a volunteer from last year?

I don't sign up for anything early but so far I have only done local races (which have race day registration). I just don't like spending the money unless I know I'm not injured. After two races in the rain last year I might also get a little picky about the weather!

For local races, sprints and occasional OLY distances, they don't tend to sell out and you can sign up until about the day before the race usually.

A lot of us are doing A races of HIM or IM. IM races sell out within an hour to a day of going up for sale usually so you have to sign up a year in advance. HIM races tend to sell out within a week to a month after.

No one knows when a race is going to sell out so we sign up as soon as possible to ensure we have a spot in our favorite race. I signed up for and have on my schedule Eagleman 2011 which is in June. It's already sold out.

I have all intention of trying to sign up for IMFL tomorrow. I don't know if I'll get a spot or not but the race is November 2011.

That's why we already have 2011 schedules on our plate. I'll fit in local OLYs or sprints as I can but I'll worry about those next year and probably won't sign up until a month or so before the race. Unless I want to do the Nation's Tri again, that one I'll have to sign up for as soon as it opens as well.

Often, there is a discount for signing up early.