Earlier this week I asked startups to share their Q3 growth metrics and whether they were performing ahead or behind of their yearly goals. Lots of companies responded. More than I could have anticipated, frankly. Instead of merely giving me a few data points to learn from, The Exchange wound up collecting sheafs of interesting data from upstart companies with big Q3 performance. The Exchange explores startups, markets and money. Read it every morning on Extra Crunch, or get The Exchange newsletter every Saturday. Naturally, the startups that reached out…