1.) They have a pretty good multi-file uploader, so you can take a whole directory of files and upload them at once.
2.) It's free. Many of the other sites with #1 require that you pay for it.
3.) You can tag your friends, and a notification in their news feed will pop up saying they've been tagged in a photo. And all of their friends will see it, usually leading to tags for people you don't know.
4.) Enough of my friends are on it that #3 is useful.
A lot of this is network effects - I think Flickr has all of the above, though some may be premium features. But FaceBook has a critical mass of people that check it regularly, which makes 3 & 4 a lot more useful. If I post to Flickr and tag my friends (can I do that?), there's no guarantee they'll see it.
1.) They have a pretty good multi-file uploader, so you can take a whole directory of files and upload them at once.
2.) It's free. Many of the other sites with #1 require that you pay for it.
3.) You can tag your friends, and a notification in their news feed will pop up saying they've been tagged in a photo. And all of their friends will see it, usually leading to tags for people you don't know.
4.) Enough of my friends are on it that #3 is useful.
A lot of this is network effects - I think Flickr has all of the above, though some may be premium features. But FaceBook has a critical mass of people that check it regularly, which makes 3 & 4 a lot more useful. If I post to Flickr and tag my friends (can I do that?), there's no guarantee they'll see it.