The postcard -- a photo or graphic on one side with a note and addressing and postage on the other -- was patented in 1861 by John P. Charlton. Since then, tourists and holiday makers have been sending them back home to friends and family to share their experiences abroad. Oftentimes, vacationers reach home before the postcards do.

Now, after 145 years the postcard's days are numbered, thanks to a new, free, and very cool Web 2.0 alternative. Sorry, Charlton.A site called TripDiary.com combines an easy blog service with Google Maps to create the ultimate postcard replacement.

The company claims that it takes only 30 seconds to create a trip diary (it took me 12 seconds). After that, it's very easy to add photos and comments and -- the best part -- update a Google Maps object that pinpoints the location of said photos and comments. It's so easy that even an adult can do it.

What does that look like? Here's an example. And here's another.

Friends and family can get updates via e-mail, or they can just visit your custom site or subscribe to your RSS feed.

The downsides are: 1) you can't change the design of the site or take advantage of a long list of options -- there aren't any; and 2) the company makes its money by placing cheesy Google AdSense ads on your travel blog.

But simplicity is the selling point here, and if you want the ultimate easy travel photo blog -- i.e., a running online postcard -- without any hassle or cost at all, TripDiary is for you.

I think it's only a matter of time before TripDiary and services like it kill off the venerable post card for good.