Ever have that nagging doubt if your friends actually read the forwarded jokes you keep sending them?

A new, subscription-based service called DidTheyReadIt that launches tomorrow aims to satisfy correspondents' curiosity.

The service (www.didtheyreadit.com) will notify its users via e-mail when recipients open a message sent using its technology -- including the time and geographic area in which each e-mail was read.

Alastair Rampell, chief executive of Rampell Software, DidTheyReadIt's parent company, said that he has gotten some flak from people rattled by privacy concerns over the service.

He said his service -- it costs $9.99 a month, $39.99 for six months or $49.99 a year -- is more like caller ID.

"You never really know if your mail gets through or not," he said. "Spam is so ubiquitous that it's not that rare that regular e-mail gets classified as spam."

DidTheyReadIt happens to rely on a tactic used by spammers to build their mailing lists. Each message sent through DidTheyReadIt contains a link to a tiny, invisible "Web beacon" image file hosted on the company's Web site. DidTheyReadIt will then log when the message is opened and the beacon is viewed -- assuming the recipient's mail program can display Web-formatted e-mail, as most do.

This approach also allows the service to track how long the message stays open and where it gets forwarded. It collects its geographic data by analyzing the Internet Protocol address of the computer the message is read from (this identifier is sent automatically every time you view a bit of Web content).

Unlike the "read receipts" some users attach to messages, DidTheyReadIt doesn't announce its presence to a recipient. But it can be defeated; Bryson Gordon, a security expert at McAfee Security, said turning off the display of Web graphics in your e-mail program squelches this tracking.

EBay Updates Auction Interface

Online auction giant eBay rolled out a new home page for auctioneers last week. "My eBay 2.0" offers eBayers more details about their activity; for instance, it lists how many shoppers have added an auction to their "Items I'm Watching" list.

The new version might have too many changes; some users complained last week in discussion groups that they couldn't get the new version of the software to work or found that it looked too cluttered.

www.ebay.com

SETI as She Goes

SETI@home, a program designed by the University of California at Berkeley's Search for Extraterrestrial Intelligence, turned five this week. The free, downloadable program puts an otherwise idle computer to work analyzing radio signals transmitted from space for signs of alien intelligence; while it crunches this data, the SETI software doubles as a nifty screensaver.

Users of the program -- 500,000 are active -- have contributed a total of nearly 2 million years' worth of computer time, but no aliens have been found yet.

setiathome2.ssl.berkeley.edu

E-mail Mike Musgrove at musgrovem@washpost.com. Leslie Walker is away.