I didn't mention email. I said message them using LW; aka Chat. How to Direct Connect, Browse & Chat

People have a limit of upload slots. If they are all full then you won't be able to connect to them until one becomes available. Also, some people are firewalled (not properly configured) & people will have great problems connecting. Also, some gnutella programs such as shareaza are very difficult to connect to. Also some users might be dial up users & difficult to connect to. Some users might be between a ISP that shapes uploads and that can prevent or slow sharing too. BTW under the Quality Column (see image in my previous post above), the Stars * beside the search item will give an idea of your chances of connecting, though it's not a definitive method of knowing if you will connect or not, it does help.

And then there's Beware of Fake files in search results