Used to use Yahoo for photo sharing and found it easy to use. When Yahoo stopped offering this service, I was given a choice of a number of sites to have everything sent to. Flickr was one of them and I understand that it is some how part of Yahoo. Chose that one but found that I didn't like it much. Seemed cumbersome and hard to use. Haven't changed it but may at some time. Many like it but not me.
Our daughter uses Photobucket and seems to like it. I find it has some limitations at the receivers end that I don't care for, mainly all the pictures come in small with no way to enlarge them without putting them on my hard drive first.
Have never used Webshots but many think it is great. Don't know if has changed but it used to be pretty slow due to all the ads associated with it.
I have used a couple others that no longer exist. Best one I found was the one from Yahoo but as I said, it is no longer around.
Just my .