If you added it to your shared folder & nobody can see it, you might be firewalled. Do you see the firewall icon (brick wall in front of the blue earth)?
Go into your library & have a look at the Uploads column. The figure on the right is attempted uploads & figure on the left is successful uploads. Do you see any attempts? The Hits column will show you how many times your files have appeared in someone's search results (this can be a bit misleading though, might just be one keyword that appears in an unrelated search).

If you're firewalled, most users may not be able to push through your firewall to upload! Let us know if this is your problem