Welcome back to The TechCrunch Exchange, a weekly startups-and-markets newsletter. It’s broadly based on the daily column that appears on Extra Crunch, but free, and made for your weekend reading. (You can sign up for the newsletter here!) Ready? Let’s talk money, startups and spicy IPO rumors. The week’s biggest IPO news had nothing to do with Monday’s S-1 deluge During Monday’s IPO wave I was surprised to see Asana join the mix. After news had broken in June that the company had raised hundreds of millions in convertible debt,…