A friend told me that I shouldn't use capital letters in my emails. Why not?

You can use capital letters in your emails...just don't use ALL capitals. It's considered rude. It's like yelling at someone.

Look at it this way; if you want to emphasize something in a sentence, you might capitalize the word, right? (example: "I am NOT going to do that" or "I am not going to do THAT") So if you capitalize EVERYTHING, it's like you're trying to emphasize EVERY SINGLE WORD IN THE ENTIRE MESSAGE.

People will actually feel as though you are yelling at them.

What are the pros and cons of changing your email address periodically?

Well, let's look at the pros first:

• Every time you change your email address, you start with a clean slate with all the spammers. If your current email address gets lots of spam, starting fresh may not be a bad idea.
• Internet providers like to get people into their fold by offering reduced "beginner" rates. Of course, once they've got you, you may discover that the price goes up more than you expected. Changing ISPs may get you a better rate.

And the cons?

• You run the risk of losing contacts. No matter how hard you try to let everyone know that you've changed your email address, you're bound to forget someone. Then, somewhere down the road, they'll try to get in touch with you, and won't be able to.
• If your email address is associated with things like internet message board memberships, subscriptions, or automatic credit card payments, you'll have to find ALL of those websites where your old email address is used and update them to the new email address. This can be a real hassle
• Speaking of hassles, let's be honest; it is a hassle for all your friends to keep updating your contact information. Of course, if it's just you, it's not that big a deal, but if EVERYONE starts doing it...

Update 2016: Two significant things have happened since this post was originally written, that would change my answer if I was writing it today.

• There are many more providers of free email addresses than there was when this was written. If you're getting an email address through your internet provider, you're part of a breed that is gradually dying. Getting a free email address through gmail, hotmail, etc, means that changing your ISP is not going to affect your email address.
• More and more people have their own domains. If you have your own domain, you should seriously consider getting an email address for that domain (likely, it came free with the domain; you just need to figure out how to set it up). As long as you've got the domain, you've got the email address! 

I hate getting emails from people who fill their emails with stuff like "lol" and "imho" and all that kind of stuff. It's beyond me! Any suggestions?

Unfortunately, shorthand like lol and imho have become a standard part of internet conversations, and you're just going to have to get used to it.

In general, very little "important" content is shorthanded, so you can usually get the meaning of an email even if you miss some of the nuances.

Here are just a handful of internet slang phrases to help you get started. Note: this list was updated and alphabetized in 2016.

• afaik: as far as I know
• bff: best friends forever
• bfn: bye for now
• brb: be right back
• btw: by the way 
• fwiw: for what it's worth
• gr8: great
• imho: in my humble opinion 
• imo: in my opinion 
• irl: in real life
• jk: just kidding
• l8r: later
• lmao: laughing my --- off 
• lol: laugh out loud
• np: no problem
• oic: oh, I see
• otoh: on the other hand
• rofl: roll on floor laughing
• smh: smack my head
• tmi: too much information
• wtf: what the ---
• ymmv: your mileage may vary

In addition to these, you may have to put up with "leet speak", which is almost like a code, in which letters are replaced by numbers and symbols which look similar. For example, the letter A is replaced by the number 4, and the letter S is replaced by a dollar sign. If it doesn't get too extreme, you can interpret without too much difficulty: 1 h@+3 l337 $p34k = "I hate leet speak"

Someone told me something about something called Bobby...I guess it has to do with making sure your site is handicapped accessible, or something. Do you know?

Bobby is a software tool designed to determine whether your site meets standards for accessibility. It looks for things like ALT text in your images, context irrelevant links (such as "Click Here"), text which is set apart based on color, and many other accessibility issues. The best part is, Bobby is a free tool*. Just type in your URL, and Bobby will tell you if you pass. If you don't pass (which you probably won't!) Bobby will tell you all the things that are wrong with your site.

If you work hard enough, you can make your site entirely Bobby Approved, and you can get a little logo saying so. Even if you don't want to take the time to make your site fully compliant, using Bobby and studying the results will help you get a much better idea of the problems disabled persons may have trying to access your site. At the very least, you should try to take care of the most glaring problems.

* 2016 Update: Bobby was shut down several years ago, but has lived on in various incarnations. Rather than linking to it here, since it'll probably change locations again, just go to Google and search on "web accessibility evaluation tool".

A year after responding to this question, the following question was received:

Dear Professor Puzzler I was reading your blog, and in particular I saw your answer to the question about "Bobby." Can you tell me why YOUR website does not pass Bobby's analysis? 

This is a good question! In my previous Bobby post I said:

"Even if you don't want to take the time to make your site fully compliant, using Bobby and studying the results will help you get a much better idea of the problems disabled persons may have trying to access your site. At the very least, you should try to take care of the most glaring problems."

This is exactly how I use the Bobby tool, for a variety of reasons:

• This site has design features that serve no practical purpose for navigation, but are purely for visual aesthetic. For instance, if you go to the home page and hover over any of the game links, they will slightly change color. This is just an attention grabber, and serves no real purpose. Bobby complains that the code doesn't run when the element has keyboard focus. Except...it's not possible for that element to have keyboard focus, so Bobby's suggestion is not practical or sensible, because he doesn't know the purpose of the code.
• Similarly, I have features that run off either a mouse click event or a link click. Bobby recognizes that I have mouse-click events that aren't keyboard accessible, but has no way of knowing that I have accessible links that do exactly the same thing.
• By the nature of this particular site, which contains a lot of educational games, some of the features may not be accessible to someone with certain disabilities, and it would be virtually impossible to make them so (in some cases it might be possible, but because this is a free site, and we would need a sizeable grant in order to be able to afford to incorporate handicapped accessibility into the games!)
• There are some links on this site which have no text in them. For a very specific purpose. They lead to secret, hidden, "easter eggs" on the site.  Adding text to the link defeats the purpose of the link. Besides, since these links are designed to be non-obvious, they're actually more accessible to someone who navigates by keyboard, since the focus will stop on the link.

For the most part, the reasons have to do with the fact that an automated tool can't guess at the purpose of an element on the page, and therefore I consider it to be more important to follow the spirit of the law instead of the letter.

Good grief! What is up with this? My friend emailed me a database file, and Outlook tells me it won't let me receive it. Have any suggestions?

This may be moderately annoying, but it is in your best interest to have Outlook do everything it can to protect you from malicious code which may be hiding in database files and executable files. So you may not be able to open that MDB or EXE file your friend sent you.

But don't despair, you can get around Outlook if really need that file. Email your friend back and tell him "I need you to change the file extention to .MDX (or anything else besides .MDB) and then resend it to me."

Your friend changes the file extension, Outlook no longer recognizes it as a database file, and it lets it through. Now, when you save the attachment, you've just got to remember to change the extension back to .MDB and you're good to go!

2016 Update: This is not just an Outlook issue anymore. E-mails tend to get checked for potential viruses at every step along the delivery process. And some services are downright scary in how sophosticated their checking algorithms are. I have a client that I do VB.net development for, and occasionally they need me to update a single *.aspx file and e-mail it down to them. But their mail server rejects as hazardous any e-mail with the *.aspx extension.

No problem, right? Just change the extension to something like *.asz.

No dice; their server still rejects it.

Okay, so let's try zipping the *.aspx file. Nope. Still no joy.

Change the file extension, then zip it?

Their server is smart enough to still recognize as potentially hazardous.

Change the file extension, zip it, change the zip file's extension from *.zip to *.ziq. STILL no luck.

Give up and mail the updates to my contact person's personal e-mail address.