Again I've been uploading photos into Flickr for a little while now.
It's a great way to share photos with family without having to send multiple emails with half a dozen picture attachments. I can also use it to create slideshows on the blog I share with family - one big Springwood Colquhouns one or separate ones for different events such as holidays we've taken. And sites like Flickr allow a little bit more security for your photos as an offsite storage - won't have to worry about everything going up in a puff of smoke next fire season.
Yes I have privacy concerns, especially since I put pictures of my children up there but if you close your photos off too much some of the people you'd like to have viewing them won't be able to because they aren't very technology savvy. I figure we're obscure enough not to worry about getting lots of people looking at our photos, although did get asked to allow co to use our pics a few months back - I told them no.