Payment for order flow. Good and bad. The no-commission trades are great, but then there's the downside. This morning I placed a trade on Etrade that should have been immediately executable. It sat there while whomever they sent it to decided whether or not to frontrun me. I clicked over to IB where I pay commissions and got the trade made before I got the execution over at Etrade.
I have seen lots of $1 stocks with strong earnings and solid balance sheets triple, quadruple and more, but I have yet to see one go below zero.