Ms. Linkfield, who also confesses she has a text-message alert that whistles ("I was getting dirty looks" for that, she says), gave up on the line's Quiet Commute cars.

WSJ: Shhh! 'Quiet Cars' Turn Commuters Into Librarians

He said staff refused to sell him the product after an alert message was displayed on the till.

BBC: Tesco burgers

Programs like Outlook allow you to turn off any pop-up messages that alert you to a new message.

CNN: Experts: Goof off at work, read a book, ignore e-mail

When a trap counts more than 10 flies in 30 minutes, or when the forecast model predicts a rapid surge in the fly population, it triggers an alert and sends a text message with the warning to farmers' mobile phones.

BBC: Black eggs and ripe guava lead Taiwan's tech revolution

Vehicle Location Alert: Subscribers can set up email or text message notifications to let them know the location of their loved one's vehicle.

ENGADGET: OnStar Family Link brings loved ones closer together through vehicle tracking

Users can personalize the system to send them an alert before they leave home or have SYNC read the text message in their vehicle.

ENGADGET: Sync adds turn-by-turn, traffic reports for some 2010 Fords

The Web admin can decide to send a text message back to the sender to verify the information, send out a blast alert to large numbers of people or post the information onto a Web page with location information from Google Maps (or do all three).

FORBES: Citizen Voices