To be sure, we live in an over-sharing world. On Facebook, millions of questionable party photos are shared daily, documenting things that many of us later regret. But what if you want some discretion, such as when you have just returned from a corporate retreat or some other event? You want to take the output from your group of several amateur photographers and just share this among the group. The challenge is that you want to keep them private to the participants and not plaster them all over the Internets. What to do?

Consider that your requirements are to satisfy the ultra-paranoid in the group and also something that is dirt simple to use. You don’t want everyone to join a new social network: most of us have too many logins already. This means most of the microblogging sites are out. And you don’t want to have to worry that someone will click on the wrong button and share the entire photo collection with the universe inadvertently.

Facebook is probably the first site that comes to mind for sharing photos. But trying to stay on top of its ever-shifting privacy controls is vexing, and besides, it is almost too easy for one of your group members to inadvertently share a photo that you would rather not have in general circulation. So that’s out.

What about LinkedIn? It is the go-to social network for business purposes. But alas, you can’t really upload any content that isn’t already out on the Internet somewhere. Too bad, because it has some very solid privacy controls in place. The other downside of LinkedIn is that getting one of its groups setup is an exercise in patience. I call it “triple opt-in.” For one of my groups of about 60 people, it has taken the better part of six months to get everyone to become a member.

And some of the same goes for other social networking sites, including Google+. While you can set up specific groups of users called “circles” in Google+ that will limit who gets to view the pictures, one mistake and your work is on display for the whole world or inside Google’s indexing maw. You want something that can set up discrete privacy controls for your group and not have to worry about it if you don’t check all the right boxes. The photo sharing part comes from Picasa, which once was a great photo sharing site, but now has been tricked out with all sorts of Google+ tagging baggage.

You could start a private mailing list group and upload your photos there. For example, Yahoo Groups is a free service and has the ability to support uploaded photos. But starting up a mailing list can be cumbersome, and might be overkill for your purposes.

Then there are dozens of file sharing sites such as Box.net and Evernote that make it easy to share general files in the cloud. These will keep your information private, to be sure. But you really want something that is designed around uploading and sharing images.

Fortunately, there are many photo sharing services out there designed for this purpose. We looked at six of them:

• Shutterfly.com
• Photobucket.com
• Flickr.com (now part of Yahoo)
• Zangzing.com
• SmugMug.com
• Posterous Spaces (now part of Twitter)

None of these services is perfect. They fall into two broad categories: those that have better privacy controls or those that are easier to use. Let’s look at our requirements in more detail. First, you want a service that can create a private space that doesn’t appear on search engines or that any random user can find. Photobucket and Shutterfly both do this, by setting up a special URL (Photobucket.com/groupname or Groupname.shutterfly.com) for your group. For Photobucket, for example, you have three choices for each album’s privacy controls: everyone can see them, no one else can see them, or you can password protect them by invitation only. The latter is what we want to use and you can set up an album password so that only those folks who know the password can see and download the photos. (See the screenshot below.) Shutterfly has similar options with its share sites option.

The problem for both Photobucket and Shutterfly is that you need to become a member to upload any photos: that is fine if you just have a few shutterbugs in your group, but if you have lots of sources of images, it can become cumbersome.

SmugMug has lots of granular security controls for its service. You can set up your photos on a special site username.smugmug.com for example. But there is a lot more: You can prevent Google from finding your photos with one mouse click, and add watermarks with another. You can add password-protection to your albums, and even provide another password for guests to upload photos to a particular album, so they don’t have to join the service to share their work. Here is a screenshot of its many security controls:

Flickr has URLs for groups, such as http://www.flickr.com/groups/groupname. But Yahoo really wants you to sign up to its service, and you will need to do so if you want to post any photos. Flickr has a guest pass option but it is somewhat clunky. Also, if you are using Flickr, make sure you have turned off its autoposting/notification features if you want to keep your photos from showing up in your Facebook timeline or other social places.

Zangzing.com is better at ease of use but it comes at a cost. You can set up individual albums that have their own URLs, such as http://www.zangzing.com/username/albumname. There is no password required so anyone who knows the URL can access the entire album. And if you want to upload pictures, you will need to join. You can also email pictures to albumname@zangzing.com and they will be automatically posted to the album, which is a nice feature.

Finally, Posterous is more of a blogging site than a photo collection, but it can be used for sharing photos, as well. Indeed, if you want to mix your photos with other business content, Posterous could be a good choice and could serve as the base for a simple low-end Web presence. Groups of photos can have their own URLs, but you do need to become a member to post content. You can also email your photos and have them posted to your site, like what Zangzing does.

There are lots of other photo sharing services, including Instagram.com, Klip.com, Twitpic.com and Pixable.com. Most of them aren’t focused on privacy but in making it easier to share photos across the universe.

Recommendations: Start with SmugMug

We recommend you start with SmugMug, especially if you require the simplicity of a shareable URL and don’t want to mess with having each person sign up for the service. If you need the additional security that a membership site offers, then look at Photobucket. It has more granularity for the security options than Shutterfly. If all the bells and controls of SmugMug are daunting, then take a closer look at ZangZing. Steer clear of Flickr: Its interface is somewhat long in the tooth, and it is too easy to click on the wrong button and end up sharing your entire photo collection to Facebook or Twitter. If you have more confidence in your users’ abilities, you can set up private groups in Facebook or Google+. Finally, if you have yet to join the blogosphere and want something simple to set up that will include a lot of photos and other illustrations, then Posterous is where you should start.