Update: See also Part 2 
When all the dust had settled and the knife rampage in Tokyo's Akihabara district  last Sunday, which took the lives of seven people and left at least 17 injured, had come to a close, many were left wondering what it all really meant. Some pointed the finger at video games , while others pushed for stronger net monitoring . But while news media commentators tried to ease anxiety  [ja] that there might be deeper social forces at play in murderer Tomohiro Kato's motives, bloggers offered less simplistic interpretations.
Video taken just after the killing
One of the common themes that many bloggers were writing about are the conditions of so-called temp workers (“haken rōdōsha”, or in Japanese 派遣労働者). Between 2000 and 2007, the number of temp workers in Japan, hired on short-term contracts at lower wages than full-time employees and with very little job security, increased by 4.5 million . Kato worked at an automobile factory  of Kanto Auto Works  (関東自動車) under Toyota, contracted through temp agency Nikken Sogyo Co.  [ja] (日研総業).
At the webpage of allneetnippon , an NGO tackling the problems of Japan's working poor, director Yamamoto Shigeru (山本繁) gives an indication of what temp work is like :
The kind of fixed-period work that you get in temp employment hardly ever results in stable relationships. You switch workplaces every 3 months or one year, or at most every two or three years. And this is not just you [it is other people as well], so isolation will further increase….
I had a look around at various places on the net about the incident yesterday in Akihabara,and my feeling [from what I found] is that isolation is giving birth to a despair. Working at an auto parts factory in a rural place like Shizuoka, living in a single-room residence prepared by the temp agency, is there any more lonely, any more painful a life than this?
In an article at magazine9, Amamiya Karin (雨宮処凜) describes meeting someone  who had been working at a Toyota factory through the same temp agency:
At the end of last year, I met a guy from Nagoya. Just like the offender [Tomohiro Kato], he had been dispatched by Nikken Sogyo to a Toyota car frame factory in Aichi prefecture, and received a notice on September 18th that: “On October 10th, your employment will be terminated.” Luckily he had joined the labor union so he entered into collective bargaining, and he was able to win “one month of life security”, “guarantee [that he could stay in] the dorm (where he had been living up until then)”, and “referral(s) for future employment”. But in that period of one month, Nikken Sogyo [the temp agency] did not refer him to a single job, and when the one month was over his wages stopped and he was thrown out of his dorm which he had been renting from the company. As a result, he ended up on the streets, and within a short time he was admitted into a Nagoya homeless shelter.
Blogger qushanxin brings up the issue of discrimination  against so-called “NEETs ” and “freeters ” in Japanese society:
The social movement surrounding poverty centers itself on [the issue] of survival, but actually it must at the same time also question the problem of discrimination. I say this because, suppose for example that the demands for standard livelihood protection and social security of the people called “freeters” were satisfied, this would just cause the resentment that “our tax money is going to those guys who don't even work hard…” to build up among regular full-time employees with stable work (there is a fine line between this idea and the racist theory of “foreigners who do not even try to blend into Japanese society…”). I've written this many times before, but the problem of survival has to be discussed together with the normative problem that employees of McDonald's and convenience stores must be recognized as “true members of society” [shakaijin]. Both problems are closely correlated, and I think it is thus extremely dangerous to separate them and deal with them on their own. One can sense in the movement right now for “survival” an atmosphere of “we can think about the troublesome normative issues once survival is satisfied”, but what I want to say is that this [thinking] is totally mistaken.
I am not sure if this relates to the incident in Akihabara, but if we take the above to be true, then rather than interpretations without any substance by people with titles like criminal psychologist about “people who crave the limelight” and “release of dissatisfaction”, one should instead consider the possibility to be stronger that he had hatred for the “average citizen” like those walking around Akihabara (even if in actual fact this was not so). In other words, for people like those referred to as “freeters” and “NEETs”, it is exactly the “average citizen” who every day targets their gaze of contempt and discrimination at them, and this is why they attack them; it would seem easier to come to an honest understanding [of this issue] by thinking about it in this way.
At a thread on 2channel titled “Kato is our friend” (加藤はおれたちの仲間), differing views were expressed . Some disagreed with the title of the thread (comment #11):
11：名無しさん＠毎日が日曜日：2008/06/08(日) 23:06:03 ID:OzKp/XrY
This kind of terror will not improve the world. [It has the] opposite effect.
The ones who are the most pleased with this incident are those from the winning side.
Kato is a complete idiot, a traitor who thoroughly fell for the trap set up by the winning side,
a negative campaign against the working poor.
Comment number 16 disagreed with criticisms of the temp employment system:
16 ：名無しさん＠毎日が日曜日：2008/06/09(月) 00:01:22 ID:m9O5agz5
There are a lot of threads on the Akihabara indiscriminate murder incident attacking the temporary employment system, but seems to me that they're criticizing the wrong thing.
Countless examples have come out of people who would be homeless if there was no temporary employment system.
In the end he depended too much on the kindness of others, it was a problem of skill, and he was working at a temp job because he was picky about his work.
There are hundreds of thousands of nominally full-time workers whose wages are lower than temp employees in urban areas, who get no bonuses and who are treated badly.
Temp agencies are not bad, nor is society. It's all the individual's responsibility.
Many however expressed sympathy with Kato, like this one (number 18):
18 ：かばわ(2チャンのドン)：2008/06/09(月) 12:58:38 ID:+aeuC22C
加藤ありがとう 勇気を与えてくれて 感謝してる
It's bad to say, but it is thanks to Kato that I've gained confidence.
I wouldn't go as far as to do what he did, but I think I could do something amazing now.
Thank you Kato – You have given me confidence – I am grateful
Blogger naoya_fujita at the deconstruKction of right, though, doesn't buy the arguments  supporting Kato on 2channel threads and in blogs:
First of all, if he is a representative of the gloom of young people about employment, then why did he choose the same young people as his victims? Did he think of them as his enemies because they were enjoying consumption in the festival city of capitalism? The enemies he should be aiming at are the establishment class, or the economic elites, no? Of course, I absolutely do not agree with something as terrible as a mass stabbing, but just for argument's sake suppose that you were going to do something, and suppose that as a measure of last resort you were going to use violence, you should minimize the damage while maximizing the effects, and if you were going to really do it you should do something like blow up the Keidanren or break into the National Diet. Why didn't he do that? It's because he can't go near them.
The establishment class suggests security in a public and private setting. Forming gated communities, installing security guards, switching to auto-locking [doors]. Poor people like me can't live in [places] with autolocks. So what is this about? What I am saying is that even though you carry out a massacre, the ones who are killed end up being poor people. People without any extra money to pay for security end up being the ones that are killed the most. Which is to say, the reason is that if you think about it from the view of the establishment class, it is better to point to people's personal security than it is to spend money reducing the risks involved in caring for the poor (by putting down rebellions and preventing left-wing revolutions from happening); if poor people commit murders among the world of the poor then so much the better [from the point of view of the establishment class] — seems to me that is the way this situation should be analyzed. That's the security society. So threats of “don't drive us to poverty or we will become so miserable that we will explode like this!” have no effect. [You get a response like]: “If that's the way it is, then we'll raise security and get rid of you guys.” And when that happens, you end up murdering not the true enemy, but your fellow companion. What you get is a picture of hell, like the mass stabbing that happened this time.
The location of the killing was the discussion topic of many blog posts. Blogger paraselene at END_OF_SCAN was almost in Akihabara when the killing happened :
Just by chance there was some talk last night about ramen in Akiba, so I was thinking that I'd go find a good ramen place and have a bite to eat. I shiver when I think that if things had been just a little bit different I might have been there when it happened.
When I saw the disastrous scene at the intersection, I absolutely couldn't stay there. It was close to anarchy, and I wasn't sure if there was still any danger.
In a post that was bookmarked by many Hatena users  [ja], blogger klov asks why Akihabara has become a place for “spectacles” :
Up until now, it had the atmosphere of a place where a variety of so-called otaku gathered with the intention of communicating, but through recent media exposure common symbols in the city called Akihabara have been uncovered, and its atmosphere has become oriented toward spectacle. It would seem that the mourning of otaku that “the Akihabara we knew has died…!” points to the transformation from a communication-oriented space to a space that, roused through the media, is oriented toward spectacle.
For much much more about this story, see a fantastic round-up by north2015 at N.S.S.BranchOffice  [ja]. See also the last messages (explained in this Mainichi article ) posted by Kato in Japanese, reproduced by blogger coldcup  [ja]. For more background on Toyota's changing business strategy (related to the use of temp workers), see this article from 2007 .
Thanks to Taku Nakajima  for link suggestions.