I'm late to this, but I've been watching people put up pictures on Flickr for awhile now - but I've only just begun to use some of the incredible functionality of Flickr the way it's supposed to be used.

It's amazing. 

 Coolmel has been doing this awhile, and take a look at a slideshow collection of his on impermanence. In the upper right there is a "speed" meter - I recommend setting this to 2 to 3 seconds.

It's simply a gorgeous collection of photographs - truly stunning.  For me, the "slideshow" functionality of this is what attracts me.  I like the fact that WORDS are gone, but there is still motion, movement, in the slideshow function.

Also, you can collect your own slideshow, based on TAGS people have submitted for photographs!

Take a look at this slideshow collection for the TAG enlightenment, combined with the second quality of "interestingness" - a ratings system.

This collection is from all over the world, and it is simply wondrous.

Again, I recommend setting the speed of the tag to something you are comfortable with.  I also recommend listening to music, that is at the same "beat" at which you set the slideshow.  For me at least, it increases the depth at which I am touched. An an example, looking at Coolmel's  "impermanence" set while listening to Enigma 2 "The Cross of Changes", set the slideshow speed to 4 or 5, well it just works incredibly well.

Or, you can go a different speed - try the slideshow created by searching for tags "France Bike Race", set the slideshow to the fastest rate of 1 slide a second, and then listen to Fatboy Slim's "Push The Tempo(Ya Mama)"

A completely different experience!