Friday's run in Nucor ( NUE) is a good "tell" for the broader market and suggests the economic cycle isn't overextended, Jim Cramer said on CNBC's "Stop Trading!" segment Friday. The fact that "copper is up and gold is down" shows that people still believe in growth with low inflation. It's bullish, Cramer said. Cramer praised the Nasdaq ( NDAQ) for its unsolicited $4.2 billion bid for the London Stock Exchange and said the New York Stock Exchange ( NYX) should be looking at something similar. He said other exchanges like the Chicago Mercantile ( CME) and CBOT ( BOT) also need to find a way to grow. Cramer said Sharper Image ( SHRP) has been victimized by a series of articles saying its best product, the Ionic Breeze, "doesn't do anything." "This is a once hot stock that isn't so hot anymore," Cramer said. He advised staying away from retail.