Helping people with computers... one answer at a time.
I sometimes get e-mails from a friend with massive downloads - 10 minutes to download a 15-second "cute" but meaningless video. When I download these things, are they copied to the hard drive somewhere? Should I periodically go in and clean them out? If so, how? I use Yahoo e-mail. I haven't noticed any particular slowing yet, but if these 2-4 meg files are sitting somewhere on our hard drive it's bound to add up at some point.
I love cute videos as much as the next guy, but sending them around as email attachments is just wrong. They take up way too much space, and take way too much time to download. In an ideal world, the videos would simply live on the web somewhere, and we'd just email each other a URL to the video, rather than some huge copy of the video.
But we don't live in an ideal world, so how best to manage what people send you?
In your case, you're probably in great shape. Using a web-based email interface, such as Yahoo or Hotmail, the browser takes care of managing your disk space for you.
Yes, the files are downloaded to your PC in order to be viewed, but they're placed in the "Temporary Internet Files" folder, or an equivalent. Browsers such as Internet Explorer automatically manage that space, and delete least recently used files when it fills up. You can control how much space is allocated to these temporary files in the browser options, but for the most part you won't need to worry about it.
If you receive email using a regular email client, like Thunderbird, Outlook Express, Outlook, Eudora and others, you need to be just a little more diligent.
To begin with, the message, including the huge attachment, is downloaded and stored in your email folders. When you then play the attached video, the mail program copies it to some temporary location - usually your system's TEMP directory. When you close the video player, and close the email that had the attachment, the temporary copy may, or may not, be deleted. The good news here is that Windows' Disk Cleanup wizard will clean up any remnants in your system TEMP directory.
Naturally, you'll need to delete the email from your mail folders when you're done watching the video. In most cases that will simply move the mail to a "recycle bin" within your email program. If your mail program does this, then to really delete it you'll need to empty the recycle bin. Even then, you may not see the disk space recovered until your mail program has "compacted" its files. Most will do this in idle time while you're not using your computer, but most also have an explicit "Compact Now" option that will force the operation to completion. Once that's done, you should see the disk space return.
The good news here is that, for the most part, you needn't worry too much about any lasting effects on disk space resulting from the huge attachments your friends might send you. The normal behavior of your web and email programs should handle things without your needing to take additional steps. At worst, you might want to run the disk space cleanup utility every so often.