Karen uses Dropbox, and wants to share files with people who don't have--or want--a Dropbox account.
Almost everyone who uses Dropbox knows that they can share files and folders through it. Yet a great many of them, perhaps the majority, do it the wrong way. I can't tell you how many times I've heard someone erroneously claim that someone else needed a Dropbox account to access shared files.
That just isn't so. Unless you want to give other people the ability to alter your shared files or folders, those other people don't need a Dropbox account. All they need is a browser and an Internet connection.
Dropbox offers two approaches to sharing: a regular share and a share link. The regular share is the best known, but in most cases a share link makes more sense.
When you invite someone to share a folder the regular way (the folder must, of course, be inside your Dropbox folder), and they accept your invitation, that folder downloads into their Dropbox folder. When either of you change the folder's contents, the folder gets synced on both Dropbox accounts.
This requires everyone to get their own Dropbox account. And a free account may not be sufficient if the folder you're sharing contains many large files. If they have a new, free Dropbox account--which is likely if they signed on--space will be limited.
A relative recently invited me to share a folder that contained almost 2GB of data. That would have nearly filled a new, free account.
That's why, in most cases, I prefer using a shared link. This makes your files accessible on the Web to anyone who has the URL. All they have to do is click the link and download the files.
By the way, these shared links have become my favorite way to share photos with friends and relatives. The Web page displays large thumbnails (Microsoft would call them tiles), which you can double-click for a full-screen image and slideshow.
To set up a shared link, right-click a file or folder within the Dropbox folder and select Dropbox>Share link. A Web page will come up in your browser, with a dialog box for inviting people via email. I recommend you simply click the Get link button in the lower-right corner, then use your preferred email program.
Of course this solution isn't right for everything. If you're collaborating on a project where other people need to edit files, a conventional share makes more sense. And since share links are available on the Web without encryption, you do have to be careful about what you put in them.