German media conglomerate Bertelsmann AG said yesterday it had bought a majority stake in internet retail search engine DealPilot.com AG under its avowed strategy to assemble a portfolio of internet holdings. The firm didn’t disclose what it had paid for the 50.1% stake in DealPilot.com which scours the web for the cheapest books, music products and videos. DealPilot.com founded by two German students in 1997 claims 1500,000 users each month, drawing 75% of its revenue from the US.