There's a new mystery to solve for fans of "The Da Vinci Code" who also use Google's personalized home page feature.
Google says it's taking part in the marketing blitz for the "Da Vinci Code" movie by conducting a contest. Each day between April 17 and May 21, a puzzle based on the best-selling religious mystery thriller will appear on a participant's personalized Google home page.
Solve all the puzzles, and you get a chance to win airfare, televisions and other prizes, Google explains at this Web site.
Here's the mystery: Aren't those ads? It's clear to some that what Google's actually doing here is introducing the first-ever ads to appear on these particular Web pages. Does that mean the ad flood gates are now open?
That seems to be the case to Danny Sullivan, of the search engine news site Searchenginewatch.
"Is it true? Marketers wanting to do the same, clearly the door is open," he wrote April 13.