I run a small site: www.mrx.no , it's a photo site for 20-30 photographers, and we all post our photos on it. As photographers, we all take a lot of photos, some are for magazines, some are for family, some are for friends, some are memories, some are for competitions and so on. With G1 it's very hard to structure a lot of photos. The first structure that comes to mind is one album per "event". E.g: A family party, A soccer game, A concert
If I continue this structure my site will have a loooong list of albums, very difficult for users to locate the photos they want to see. I can try to avoid this by adding sub folders to my gallery: Family, Sport, Travel, etc, I can even add subfolders for an event, I shoot ten bands at a festival, I wanna add Concerts (to group music photos) -> woodstok 2005 (the event) -> Foo Fighter,etc (one of the concert)
With AlbumTags, I could add a "ConcertTag" to the "event" album, and I could add a Music album that was to only show albums with the "ConcertTag". Basically the same as I do now, just done with AlbumTags. But, since I run a site with multiple photographers on it, I can now create a root Music folder, and if everyone on my site used the "ConcertTag" on their music albums, I could have a common album with all the concert albums for our site.
There are endless possibilities with this feature that enables you to "group" albums dynamically. It will also enable me to show albums at more then one location. I can have a rock album: which then has "RockTag", but i want the albums with rock bands to be in both Concert album, but also in my Rock album. I may want to create my "rock" album in a completely different folder then concerts, which I now can.
[Photo Tags] Look at Flickr.
So, i got 20-30 photographers, all very good and all uploading a lot of photos. We, as a team want to have a album on the main page, that shows the best of our work, a Portofolio folder. Here we could add an album with the Phototag: "Best", and if some of the users think this is worthy of adding to the Portofolio folder, they would add "Best" phototag to their photo. It would remain in their orginal folder, but it would also pop up in the "Portofolio" folder.
Lets say I want to add a album called colors, I add sub albums called red,green,blue,etc. I add the Phototag "Red" to the Red Album, etc. Now, if I add a "red" "blue" "grey" etc tag to all my photos, I could suddently "view" all of my RED photos in one album. Cool In other words, I could group photos by terms I find interesting, and have them show dynamically. Good examples would be: Persons name, locations, subjects, colors, art-styles, yeaar, rating, series, projects, weather, etc. Gives me a lot of flexibility and power.
This was just a quick example how I envision PhotoTags and AlbumTags, and why both would be a great idea to me. Maybe it'll help some of you see some benefits, maybe some of you don't see the point at all. but at least, let's discuss it!