Let's think about mass shootings.

[2dimes]

Where do you think the term, "going postal" comes? Most were before Columbine.

[john9blue]

i didn't really pay attention to news when columbine happened, but i can imagine that it set some kind of precedent for all these school shootings.

[BigBallinStalin]

Maybe something like this, bbs...
http://www.motherjones.com/politics/2012/07/mass-shootings-map

The killers: Half of the cases involved school or workplace shootings (12 and 19, respectively); the other 31 cases took place in locations including shopping malls, restaurants, and religious and government buildings.

Based on this, 19 workplace shootings would equate to "corporate spaces" right?

It would help to collect data since the 1970s or 1980s--whenever this phenomena began.

[Dukasaur]

i didn't really pay attention to news when columbine happened, but i can imagine that it set some kind of precedent for all these school shootings.

The Grover Cleveland Elementary shooting was long before Columbine.
http://en.wikipedia.org/wiki/I_Don%27t_Like_Mondays
I notice it doesn't make it onto the Mother Hubbard list that stargazer posted, presumably because Spencer had terrible marksmanship and none of the kids died, but I think it did start the trend towards attacking schools.

The postal shootings were in 1986, and yes they did inspire the expression "going postal."

I'm not sure if the location is quite as significant as the relationship of the shooter to the victims. Both at the post office and at Columbine, the victims were known to the killer and were being shot for perceived social crimes against the killer. This is quite different from most of the schoolyard/MacDonalds/shopping mall shooting sprees where the killer attacks random victims mostly unknown to him.