What's considered "Traction" in the B2C app world these days?

Mobile app that has launched: You need ALL of the following:
1) Trending towards or at 100000 installs within first 90 days of launch;
2) Day 30 retention rate of at least 20%
3) Core "MTM" (metric that matters) healthy (dependent on business model, usage model etc)
4) Evidence that growth is just "getting started" with plenty of upside left.

Happy to talk more in a call.

I'm a developer, not an investor, so it's difficult to give you specifics on the metrics you mentioned, but from my very hard-earned experience, you want to be able to demonstrate the following, to get an investor interested:

1) Solid product-market fit, in terms of your value proposition and how it is meeting the needs of your audience.

2) Community exposure. Is your app being well-covered by the main blogs and networks in your niche? What are your conversion rates for new visitors or linked content?

3) Can you accurately measure churn? User return rate? Daily active users? Small but consistent user base is what they want, rather than large but sporadic.

4) What feedback you have had. Positive and negative. Negative is good because of point 5.

5) Show how you act on negative feedback. If an investor can see that you are listening to, and adapting to your audience feedback, they know you really care about the end user, not just fulfilling your grand startup vision.

6) Show your roadmap (including historic). In my experience, investors need to know what their money is going to be spent on, how those decisions are being made, and have been made in the past.

I've been involved with a dozen or so startups myself, and have consulted with many more, so if I can offer you and more advice, or if you would like your deck reviewed, feel free to get in touch.