Occasionally, when an article in Swedish needs to count off three items, they are not labelled "1, 2, 3" but rather "1, X, 2". Why is that?
I asked Jesper Holmberg, and he was kind enough to explain. (The entire exchange naturally was conducted in Swedish. Here's my translation.)
As with most of the good things in life, it has to do with football [soccer].
In Sweden, it is not only legal to bet on horse races, football, and other stuff, but the Swedish government even has its own betting agency. "One, cross, or two" comes from the betting ticket, the slip of paper you fill in when you bet on football or hockey. The ticket consists of thirteen matches, and for each match you choose whether you think the home team will win (1), whether the visiting team will win (2), or whether you think it will be a draw (X). You can see an example of the ticket by going to http://www.svenskaspel.se/ and clicking on "Stryktipset" in the upper left corner.
If you want, you can, in one or more matches, choose two options, if you, for example, think that the home team is going to either win or draw. This is called "half-covering" (halvgardera). You can even mark all three, which is then "full-covering" (helgardera). The odds of winning goes up, but also the cost of playing. (My grandfather and I would bet on football on the weekends when I was little; it took us hours to fill in the ticket, analyze statistics, discuss odds, the payouts... I don't think we ever won a dime.)
So this is how I interpret why that blogger you linked to chose 1X2 instead of 123: The point he's trying to make is that the answer is somewhat random, possibly even unknown. With 1X2, there's more of a sense of betting on circumstances one doesn't control, while 123 is more of a quiz where it's up to you to win or lose. I dunno, maybe I'm overanalyzing. Maybe he's just got a gambling addiction!
I thanked Jesper for his explanation, noting that I had been wondering about this for many years. "Now it makes sense. No, I'm lying. It doesn't make sense, but at least it's less confusing. It was more like a joke targetting people who bet on football or hockey! On the other hand, it's probably impossible to find a Swede who doesn't bet on football or hockey..."