First, what are the key differences between POP3 and IMAP?

POP3 is a transfer tool
POP3 is really an email transfer protocol.  Think of it as downloading messages from the server and moving them to your PC.  They are initially stored on the server, then your email software downloads them locally to your computer and removes them from the server.  Now only your PC has your email messages.  Any new messages will arrive at the server and wait for your PC to pick up and move the next batch.  With POP3, your “inbox” is effectively stored on your computer.  That typically means that only one computer can be used to manage your email, and you can even work with your email messages while you’re offline.

IMAP is like a looking glass
IMAP is different from POP3 in that it lets you look at your inbox on the server.  All of your interactions are done live over an active Internet connection, and you manage your messages as they exist on the server itself.  The benefit is that you can then manage your email from multiple computers since the messages are maintained on the server and not pulled down to any one computer as with POP3.  It does require an Internet connection, however.  So offline email management is not possible. Today, with always-on broadband access, this is usually not a concern.

I do email from one computer only
POP3 is perfect for you.  As your computer picks up email from the server, it is then stored on your computer and removed from the server.  Only one copy of your email exists then on your computer.

I sometimes do email from two computers (e.g., workstation and laptop)
POP3 at both computers might be right for you, provided your configure your email software to leave messages on the server after they are transferred.  That way, you can get the same email on both computers.  This puts the responsibility on you to manually delete and remove messages on the server, otherwise they may continue to be stored there forever.  If one of the computers is your primary email workstation and the the other is for occasional checking for new messages (e.g., a laptop while traveling or at home after work hours) then your primary email computer can automatically remove messages from the server after transferring, but your secondary should leave messages on the server.  In this way, you can go back to the primary computer (e.g., at the office) and download the messages you might have already seen when you were on your laptop.

I do email from two or more computers (e.g., PC and mobile phone)
You’re an IMAP candidate. This includes anyone who also does email from their mobile phone (yes, that’s a computer, too).  It is especially important that if you are an IMAP candidate that all of your email account settings on all PCs and mobile phones are set up to use IMAP.  If any one of them uses POP3, you’re going to have problems unless you configure the POP3 account to leave messages on the server.  Even still, then, you might as well use IMAP.

Known issues and warnings
Taking a line from the movie Ghostbusters, don’t cross the streams.  Mixing POP3 and IMAP between computers and phones while accessing the same mailbox can sometimes cause a conflict that renders the server’s inbox inoperable, requiring your email service provider to reset it for you.  Bottom line: use IMAP always on all systems when you check mail from multiple devices.

Outlook is a poor IMAP client. Unfortunately, with the ability to easily synchronize contacts, calendars, tasks, and notes, Outlook is about the only choice for email if you have a smartphone.  But due to Microsoft’s horrible implementation of IMAP, you’ll have to deal with its design flaws.  One persistent problem that is widely reported but has never been fixed is that Outlook cannot properly handle changes to your server’s inbox that take place behind the scenes (e.g., when your mobile phone checks for new messages).  Outlook will bring up an alert stating that the connection to the IMAP server has been lost.  An annoying side effect is that this causes Outlook to reset any flags you placed on messages, such as deletion.  This is not a problem with all other IMAP clients, such as Mozilla Thunderbird or Apple Mail.

Unlike POP3 users, IMAP users need to be especially cautious about storing email on the server.  IMAP excels at this capability, but it can cause you to incur extra storage charges because the server, not your computer, is where all your messages are kept unless you know how to get around this.  For long term archival of email, it is recommended that you create a local collection of mailboxes (e.g. in your Personal Folders data file in Outlook) into which you move messages from the server.  While this will cause them to be removed from the server, it will avoid storage fees.  Using IMAP folders on the server is fine otherwise as long as you are aware of the potential cost.  Also keep in mind that if your Internet connection is lost, you can’t get to your IMAP folders on the server.  So important messages probably should be manually moved or copied to local personal folder storage on your computer.

IMAP Typical Use Scenario
You’ve read some messages in your IMAP inbox and now you delete them.  Unlike POP3 where they will just disappear into the Deleted Items folder, they are simply flagged for removal (Outlook shows them in a struck-out style).

To remove your flagged-for-removal messages, you need to purge them.  In Outlook, for example, use the Purge items under the Edit menu.  In newer versions of Outlook, you can configure it so that switching IMAP folders will automatically purge flagged messages.  You can also configure your email software to purge them when you quit the program.

If you want to move a message out of your IMAP inbox and into a mail folder for longer term storage, you need to decide if you want to store it on the server or locally.  Create folders on the server or in your Personal Folders local storage on your PC and then drag the message from the inbox into the appropriate folder.  This may flag it for deletion in the inbox, so as described above, you’ll want to purge your inbox of flagged messages.

These DTL email tips can keep you, your computer, and your mailbox happy. Ignore them at your own peril.

1. Ask and Ye Shall Receive.
   People get spammed because they give their address away. If recklessly disclosing your email address has turned your mailbox into a rubbish bin, consider starting over with a new address, then heed the rest of this advice.
2. Protect One, Abuse Another.
   Maintain one email address that you defend with your life and share only with trusted souls. Freely use a second address when shopping online or signing up for newsletters. Trash your abused address as needed and get a new one. Free email services are perfect for this.
3. Keep it Off the Web.
   Never post your email address on a web site (businesses do this all the time on contact pages). If you need a contact link, encode it using DTL’s Mailto Encoder tool.
4. Beware of Web Forms.
   Many web sites ask for your email address to access special features. Sometimes an address is optional. Omit it or enter something bogus. Beware of pre-checked boxes that opt you into a mailing list.
5. Don’t Trust Anyone.
   Got an attachment from someone you don’t know? Delete it. Got an unexpected attachment from a friend? Confirm with them first before opening it.
6. Don’t Be a Legendary Fool.
   That message your friend sent imploring you to forward it to everyone you know was an urban legend. Don’t fall for it. It’s a great way to look foolish and lose control of your email address to complete strangers — folks who, if they become infected with a virus, have you in their address lists. If you must blast an email to lots of people, put their addresses in the Bcc field.
7. Watch What You Send.
   Do not include your email address in your electronic signature. It can be easily spread around by others via forwarding. When forwarding a message from someone else, you can protect their address by removing it from your message.
8. Know the Executable File Extensions . . .
   . . . such as .EXE, .COM, .SCR, .BAT, .VBS, and .PIF. If you get one of these files by email, don’t open it. A ZIP archive containing a file with one of those extensions probably has a virus. Attachments with dual extensions (like OPENME.PDF.EXE) try to fake you out. The last extension matters. To see it, use the Folder Options control panel to uncheck the “Hide extensions for known file types” item.
9. Never Respond To Spam.
   If your bank sends monthly statements you’d rather not receive, it’s OK to click the “Unsubscribe” link. But if you have spam in your mailbox from some unknown source, don’t reply or click on anything in it.
10. Stay Up to Date.
    Visit Microsoft Update regularly to apply critical security updates. If you use anti-virus software, keep it updated (but don’t bet your life on it). If you use Outlook, upgrade to Office 2003 for better security and spam blocking and make sure to keep it updated, a step many Office users neglect.

I spend a lot of time helping customers rid their systems of adware and malicious software. Despite maintaining their Symantec subscriptions, they still get infected. Yet, in over 15 years of heavy email usage without any virus software on our computers, my wife, two teenagers, and I have never been infected. DTL’s BlockSmith system does a good job of rejecting virus-ridden email. But good education and common sense beats the best software any day.

(Originally published July 2005)

While looking into this, I discovered an interesting fact that might shock you. I am about to reveal a simple test to determine your chances of being spammed. It’s so easy, you probably already know how to do it …

I want you to Google yourself.

No, not using your first and last name. Instead, put in your email address. In fact, search on all your email addresses, including your company’s “info”, “sales”, and “webmaster” addresses, too. Go ahead and try it now.

If no documents are found, congratulations! Your chances of being spammed are slim. (Do a touchdown dance and some well-deserved fist pumping.) My current email address isn’t found anywhere, fortunately. But it wasn’t always that way.

A history lesson. My original Internet address, mdavis@cts.com, was created way back in 1987. A Google search reveals 141 sites where it is referenced. In decades passed, we didn’t have to worry about email addresses leaking into public spaces online. With spammers scanning the web to abuse any address they can grab, I finally had to give up my cyber identity after 16 years.

If your search reveals that your address is being exposed, you can count on unsolicited email. Without exception, people who get spam can find their addresses on at least one web site. It will likely get worse as the spammers get more clever at finding ways around spam filters. So, this is what you need to do right now:

Remove your addresses from the web.

If you think this is unreasonable, relax. Your address can still appear on the web without being detected by spambots. If you think it is impossible, have faith. There’s always a solution.

Start by contacting the owners of the sites that are pimping your address and ask to have it removed or encrypted. That prevents new spammers from getting your address. Those that already have it will eventually be caught or blocked.

Important! If you own a web site and publish email addresses without protecting them, shame on you. You are causing grief for others by giving their addresses to spammers.

You can be virtually spam-free this year (or at least reduce the annoyance). If you need assistance, just ask.