In this segment from Where the Money Is, Motley Fool financial analyst Matt Koppenheffer highlights one financial tweet from the Twittersphere, that calls into question the celebration around Citigroup (C 0.05%) and its earnings beat this quarter. The tweet also points to the idea that Facebook (META 1.04%) could be jumping into the payments business. Matt looks at some of the other big tech giants and their payments businesses, and says it would surprise him more if Facebook wasn't making a move toward mobile payments.