2 - how much traction is enough?
Investors operate at all stages, from concept to mature businesses - depending on their risk appetite, investment horizon etc
If a startup can show traction in a chart, this should get investors excited.
The trick to demonstrating traction is to be very clear on how the possibilities on the "y axis" are off the scale (this is the size of the market you operate in), and then to pick intervals on the "x axis" that make your growth look exponential. You can use anything from days to years...etc.
Startups yet to leave the drawing board, but able to attract investors; are usually set up by founders who have built a business before. "Traction" in this case is actually the individual's "track record".
The morale of the story for budding entrepreneurs is that whoever you are working for now, whatever you are doing; do it very well! This is your "traction".