"Startup = Growth" (c) Paul Graham. Traction is a proof of massive adoption of a startup by its users. Moreover, it is a key indicator that your startup is ready for venture capital financing (Seed, Series A or Series B funding rounds). Your startup should keep at least one of the metrics below for at least six months to get the traction approval.
How did I get those numbers? As I’ve been doing marketing since 2000 I’ve had a chance to accumulate big and small data from corporations, small ventures, own startups, open Google crawlers and API’s, white- and gray-hat marketing communities, helpful insights from colleagues. The final actual numbers for the metrics you see are the results of qualitative research. That means, first, I have an average (mean quantitative) values, and then manually match it with expert numbers (median qualitative). If both data fit - we’re good. If expert numbers go out - I adopt Bayes' law and Daniel Kahneman’s methods to balance the data.
Bear in mind, all those marketing benchmarks and startup metrics below relate to the United States market only. Though they can be applied to other T1 countries (US, UK, CA, AU, NZ), these metrics don’t represent traction benchmarks for startups and companies in T2 and T3 regional markets.