What is This Thing?

Walking with friends last night, we spotted this peculiar pedestal on the corner of 11th and Ontario (here it is on Google Maps). It's about three feet high, made of granite (I think) and has shallow lines engraved into it at irregular intervals. There's some graffiti on it.

Click the dodgy iPhone photo for larger version:

Do you know what this thing is?

UPDATE: This comment, from Barb at the City of Vancouver, provides the answer.