This.

Most people fail to grasp that fact that time is a key factor in attach rate because attach rate is a cumulative element and not a snap shot of a single moment.

I prefer to use a formula that includes time as a variable.  (total software / total consoles) / number of months of availability.  This gives a more accurate and comporable picture.  Though it does have the flaw of staggered launches such as the PS3 but applying the formula to the different territories individually first solves that.

fail math..

if a console has a attach ratio of 7.5 and alot of new owners buy a console and 2-3 games with it.. attach rates go down..

seriously?

Of course the attach rate goes down if they buy fewer than 7.5 games.

From http://www.vgchartz.com/forum/thread.php?id=108794

The VGChartz attach ratios are based off of the weekly data.  If a game isn't tracked or it simply has a LTD listed on the game page (sometimes they are tracked, but also have a static number added) then it doesn't factor into the total software sold.

that post is am ok example. But if you continue to read futher on he's saying that it doesnt sell like other companys and they are only good sales when compared to itself.

As a console gets older, the attach rate rises. This is not something you can debate, it occurs.

As a first order approximation, we assume that hardware sales rate is constant and that the software sales rate is proportional to the userbase.

So when a console has a userbase of x units, it's install base is increasing at a rate of y and it is having a rate of software sales of z, this it's attach ratio will tend towards z/y

When the same console has a userbase of 2 * x units, it's install base is increasing at a rate of y and it is having a rate of software sales of 2 * z, thus its attach ratio is tending towards 2*z/y

Now, as i said before, this is an approximation, the hardware sales rate of console's tend to increase up until about the console's 3rd birthday, then they decrease. So before the 3rd birthday, the attach ratio is going to increase slower than my data indicated, and after it will increase faster. It is also not true that a console with twice the userbase will have twice the amount of sales - it so happens that the more core users buy early, while the less core users wait until price cuts, thus the increase will be slower than the above would indicate. 

In all cases, he is saying that the problem is Sony fans overhyping the games, not that the games are selling badly. 

Squilliam is not saying that GT5 will sell badly, he is saying that Sony fans are wrong to hype GT5 as much as they do - a lot of PS fans will tell you that GT5 is the generation's definitive racer, when they should infact recognise the contributions made by other games, such as Mario kart.

The only comment Squilliam makes about the sales of PS games is that they do not sell enough to warrant the reverential treatment many people give them - it is no shame to be outsold by Mario Kart, and he does not try to say there is

Those numbers seem off for some reason.

I understand what he is trying to say, people overhyping ps3 exclusives. However when others bring up sales in the thread he starts to imply they dont sell well, alot of people go the same feeling too. Read through it. I am sure there are more thread stating ps3 doesnt sell well. Why he made that thread in the first place i dont know, i havent seen anyone claim ps3 exclusives are going to do crazy numbers. Hyping a game is completely different. If it wasnt anti ps3 then why didnt he compare Forza to Mario Kart (which are  way to different)? Or simply say hey why dont we pay homage to what predecessors have done? Or just say hey can we calm down the ps3 hype! I dont really care, not really important in this thread to discuss futher.