Redfin, the Seattle-based real estate site, had a great first couple days on the stock market. After pricing above the expected range at $15 per share, the stock closed Friday up about 45% at almost $22. Today, shares were up…

Redfin, the Seattle-based real estate site, had a great first couple days on the stock market. After pricing above the expected range at $15 per share, the stock closed Friday up about 45% at almost $22. Today, shares were up…