Why do text message rates keep going up?Text message rates have doubled since 2005, from about 10 cents each to 20 cents today. Senator Herb Kohl (D.-Wisc.), who chairs the Senate's antitrust subcommittee, has asked Verizon, AT&T, Sprint Nextel and T-Mobile to explain it to him. "It does not appear to be justified by rising costs in delivering text messages," the letter says. "Text-messaging files are very small, as the size of text messages are generally limited to 160 characters per message, and therefore cost carriers very little to transmit." Kohl's suspicion: The four big carriers have increased their prices nearly in sync, suggesting a collusion to wring more money out of the market rather than to compete against one another. Read the whole thing — it's no Series of Tubes. (Photo via Gizmodo)