Companies are responding less to customer email, despite the potential for losing business, a market research firm said. Since 2000, the number of Web sites responding to emailed queries within a day has decreased to only 45 percent, JupiterResearch said in a report. In addition, the number of companies taking three days or longer, or not responding at all to customer email, grew 7 percent year over year from 2000 to 2005 to 39 percent. While 92 percent of Web sites offered email as a customer support option, only 41 percent acknowledged receipt of a message with an automated email response. Failing to maintain a high level of responsiveness is increasing the likelihood of losing customers, particular if they become angry over unanswered emails, JupiterResearch analyst Zachary McGeary said.