It's visually arresting, but I'm not sure there is as much actual information there as it appears on first glance. Is there any meaning to the position on the X-axis within a column? If not, then that is chartjunk.

Nice that you mention it. I like the way this chart looks esthetically , which is not complete drivel as some might think, but there are visual interpretation issues with comparison of the sizes of circles. I find that in most cases bars are much better.
I would have liked to have seen the chart laid out in other ways. There are several interesting possibilities using bars, groupings and colors, such as laying out the acquisitions with bars whose height represents price

order by price high to low, color by industry

order by price high to low, group by year, color by industry

order by price high to low, group by industry

I'm not sure if the place in the chart is actual date inside the year. If not, yes, it's junk, but if so, then we could also

Order by date, color by industry

Also bars will compress the visual information allowing correlations to be more easily seen. In the above diagram, I have a hard time taking in the whole without scrolling which makes it more difficult to consume a holistic manner.

Don't forget Sun Microsystems is also a Database owner (for databases category) =)