As far back as I can remember writing in all capital letters has been considered rude. Writing in all capital letters on the Internet is the same as shouting at people, it's also harder to read. Most people consider it to be just plain rude.

If you write in all caps people will think you are angry may not want to read what you're writing. If your intention is to shout because you're angry then you can use select sentences to write in all caps, but not the whole message.

Sometimes I see titles written in all caps. Titles should not be written in all caps either. The right way to do titles on the Internet is to use bold letters or to capitalize the first letter in each word of the title. There are exceptions to the capitalization of words in titles. Unless they are the first word in a sentence these words should not be capitalized; a, an, the, and, but, or, nor, for, so, yet, to.

When you are writing your profile or your blog entries keep this in mind. You don't want to alienate your friends and potential friends by shouting at them. When you send them messages or leave comments for them, don't shout. They'll get the message even if you don't write in all capital letters.