We'll give you a hint: The first of these 2,300 data points appeared at the intersection of Yonge and Bloor back in 1924.
If you guessed traffic signals you're absolutely correct. This beautiful map of Toronto was created by Redditor William Davis by using information from the city's open data portal. You can find a full-size version of it here.
Not surprisingly, the downtown area is the most signal-dense part of the traffic network. And as Chris Bateman points out in BlogTO,
What's really amazing is that Toronto, zoomed out and reduced to a collection of dots, is still easily recognizable. The negative space created by the Don and Rouge river valleys is also visible, if you look carefully, so are winding Weston Road and Dundas Street.
Redditor redkulat uploaded the data to Google Maps to create this unique perspective:
[ via BlogTO ]