The slashdot effect on websites -- a crippling rush of visitors to the website linked to by a slashdot story -- is well known. Less well known is the effect on sale of books reviewed at Slashdot. Authors, including myself have seen their Amazon Sales Rank, a measure of relative strength in sales by Amazon in recent past, soar (or dip, if you are looking at pure numbers, but a dip in Sales Rank is actually quite good) in wake of a Slashdot review. But this phenomena is relatively unknown outside the inner circle of authors.
As Amazon revises the Sales Rank every hour, and does not publish historical values, it has been hard to document the short term and long term effect of "Slashdot Book Review Effect".
Not anymore. You can use Charteous, a website that tracks historical Amazon Sales Rank and presents them through nice charts, to visually observe "Slashdot Book Review Effect". This is actually quite fun!
Slashdot published the review of CSS: The Definitive Guide on Jan 29th with a rating of 9 (out of 10, implying VERY GOOD). Watch the impact on Amazon Sales Rank thought this Charteous widget:
Warning: Charteous widgets use SVG and work fine under Firefox1.5+ and Opera9+. If you are using IE6 or IE7 without Adobe SVG Viewer plug-in then it will ask you to download the plug-in. It is okay if you click Cancel. The widget will then display a PNG image of the chart.
Not enough time has passed since the day the review was published, so it is hard to see the long term effect. But as the chart is "live", you should be able to see the effect if you come back after few days.
Let us look at another example, one that has few weeks of post review data: Slashdot published the review of Wikinomics on Jan 3rd. Here is its Amazon Sales Rank chart.
As you can see in both cases, there is a marked uptick on Sales Rank, and hence sales volume, just after the review hits the Slashdot main page. It lasts for a few days and then comes down to the normal (whatever that may be!).