Photo sharing is one of the greatest uses of the Web, and Flickr is the most popular photo-sharing Web site around, largely because it's so easy to use. But there are a few flies in Flickr's ointment that you should be aware of:

• Too adult? For some potential users, Flickr may have too many grown-up images. Despite strict rules forbidding "frontal nudity, genitalia, and intimate moments" in Flickr photos, it's not hard to find nudity and semi-nudity on the site. If you post family photos on Flickr for your children to view, they may keep looking on the site and find some things you'd rather they not see.
• Flickr's terms of service limit users to those 13 or older, but there's no way for anyone to enforce it -- probably, few users know it. So it's up to you to decide who you want to encourage to use Flickr.
• Too easy? Flickr makes it very easy to upload huge numbers of not-very-interesting photos. (Is every picture you take with your mobile phone worth sharing with the world?) You have to exercise considerable restraint to make sure all your photos are worth the server space devoted to storing them.
• Too open? Flickr has excellent privacy protections, but it's still easier to do the lazy thing and make all your photos public -- or for passwords to be shared more widely than you planned. Think twice before letting photos of, say, your kids be too widely viewed.
• Too flexible? Professional photographers are always careful to get a signed model release from everyone depicted in a photograph they want to sell or otherwise use. You don't necessarily need to be that careful -- but the jury's still out on exactly what the limits are. Be careful, especially about using photos without rights in any way that may help you make money (for instance, on a business's Web site).

Think over these concerns before you commit a bunch of time and energy to Flickr. You may prefer to put your photos online some other way. Or, use Flickr to host your photos, but put the best of them on your own site for viewing. No matter what, you have many more options with Flickr than without.