5% of text messages never arrive, according to this piece by Todd Wallack, reporting a Keynote Systems study. Depending on the urgency of your messages, that can be anything from a minor pain to a royal one.

If one bird in twenty in a flock of geese didn’t get the message telling them to turn left at Newfoundland‚àö√±

Tapping out a text message on a cell phone can be like tossing a bottled message into the sea, according to a study by Keynote Systems of San Mateo, which found that tens of millions of text messages are lost every month. Overall, Keynote found 1 in 20 text messages are never delivered. And a little over 1 percent took at least 10 minutes, if not far longer, to arrive. Worse, cell phone companies rarely warn users when their messages are lost. “I wouldn’t send anything important with a text message,” said Cody Kirkhart, a San Rafael student who has used the service for a year.

Keynote found Nextel Communications and T-Mobile had the worst performance, while AT&T performed among the best.