My criteria for hobbyjogger...
1. You take 1-2 days off completely (no running) to taper before a 5k road race. I'd add taking a day off before/after a long run to that.
2. You try (and think) you can run your best marathon off 30-35 miles per week. Or <3000 mpy
3. You think CrossFit or the like will help take your race times way down instead of adding more miles to those 30-35 mile weeks.
4. You wear special costumes on race days.
5. You race in a pair of 12ozPLUS regular trainers (not designed for racing)
6. In search for better training and motivation, you frequent the forums of RunnersWorld.com, BodyBuilding.com, and/or CoolRunning.com beginner sections. Add the Running Times forum to that
7. You think UnderArmour/NikeShox makes respectable distance running shoes.
8. Your typical training pace of ~8-10min/mile is within 1min/mile of your 5k race pace. And your 5k and 10k paces are within a minute/mile of your marathon pace
that's all i can think of for now. i dont think hobbyjogger can be defined by times per say, there can be some slow people who train smart but are still relatively slow due to lack of talent, age, etc. Most people underachieve, being slow is mostly a guarantee of it.