Interaction with your neighbours beyond seeing them get into their cars or pop out to get their mail or watching them shovel snow or garden depends almost entirely on how homogenous your neighbourhood is, and, to a lesser extent, on how the front yards/garages/porches/etc. are designed. Cabbagetown is a relatively homogenous place, so people interact more...they're comfortable with each other, speak the same language, etc. It has absolutely nothing to do with how urban or suburban your neighbourhood is. Absolutely nothing at all, unless you live in exurbia on multi-acre lots and literally can't see your neighbours (but that's not "the suburbs," anyway).
I've lived on ultra-suburban culs-de-sac (two car garages, no sidewalks, detached houses with pink brick keystones) where backyards would be unused because everyone spent all their time in the front yards, but we wouldn't just sit there and spy on each other, we'd enter and use each other's homes like Kramer used Seinfeld's apartment. People began moving away, though, and the neighbourhood became increasingly diverse...the more diverse a neighbourhood is, the less likely it is that your house will be within eyesight of multiple potential friends and a real porch culture (not just sitting out there staring as passersby) will not develop.
