Helping people with computers... one answer at a time.
Web based email services like Hotmail keep your mail on their servers. But your browser might be caching the email you read on your hard disk.
If you have a Hotmail account and you check your mail at your office, does the email go to the hard drive and how long will it stay there. Is it easy to retrieve and is it completely readable? Say an email from a year ago on a heavily used computer.
Yes and no.
Hotmail, like many other email services, is web-based. That means that all of your information, including your email, is kept on Hotmail's servers.
However, you do have to use a web browser, such as Internet Explorer or FireFox, to read your mail. That's when things get complicated.
By keeping all of your mail on its servers, web-based email services allow you to view your email from just about anywhere you can find a PC. Fire up a browser, login, and you've got your email.
So in that sense, no, Hotmail and other web-based services do not download your email to your computer.
In fact, that's one of the reasons I so strongly recommend avoiding these services for anything truly important, since you're at their mercy. You have no way of even backing up your email yourself. If the service fails, your email is lost or your account is stolen, you have no way to get it back.
However, its important to know that some of your email may be present, in a different form, on the computer you read it on in your browser's cache.
Web browsers like Internet Explorer work by copying pages from the web sites you visit down to your machine, and then displaying them. When you view your email on a web based email service, you're just viewing a web page like any other. That means it can be cached.
That also means that anyone who comes along after you could, potentially, look in your browser's cache and see the email you recently viewed.
Viewing the contents of your browser's cache isn't very intuitive, but it can be done:
Internet Explorer 6 - Click on Tools, Internet Options, then click on the General tab, and then the Temporary Internet Files Settings... button. In the resulting dialog box, click on the View Files... button.
Internet Explorer 7 - Click on Tools, Internet Options, then click on the General tab, and then the Browsing History Settings button. In the resulting dialog box, click on the View Files... button.
Firefox 2 - In the address bar type about:cache, and press enter. Firefox will list information about both the in-memory cache and the on-disk cache, and include a link List Cache Entries for each which will allow you to browse the files within the cache.
Files remain in the cache for different amounts of time depending on how big the cache is, and how heavily the browser is used. It could be a few days, or it could be months.
If you're concerned about privacy, and you're trying to make sure there are no copies of your email left around, then you need to make sure to clear the browser cache when you're done. To do so:
Internet Explorer 6 - Click on Tools, Internet Options, then click on the General tab, and then the Temporary Internet Files Delete Files... button. In the resulting dialog box, make sure that Delete all offline content is checked, and click on OK.
Internet Explorer 7 - Click on Tools, Delete Browsing History, and then click on the Delete Files... button.
Firefox 2 - First, click on Tools, Options and then click on the Privacy tab. In the Private Data section, click on Settings.... In the resulting dialog make sure that Cache is checked and click OK. You can then click the Clear Now button on the Options dialog, or simply use the Tools menu, Clear Private Data item.
On the other hand, if you're looking for a piece of email that you recently viewed in your web based email, then rather than clearing the cache, you'll want to browse it instead, using the instructions earlier. This can get complicated, as the URLs for viewing mail aren't always simple or obvious. Pay particular attention to the base domain listed (i.e. something.something.hotmail.com or perhaps something.something.hotmail.msn.com), and the type of file being accessed (often ".htm", though Hotmail uses something called /cgi-bin/getmsg with a long string after it).
It may take some work, and to be honest what you're looking for may not be there - it may already have been cleared out of the cache. But depending on your situation, it may be worth the effort. Just remember that the more you use your internet browser, the more things will be "pushed out" of the cache to make room for the new pages you're visiting.