10 Common English Grammar Mistakes

In reviewing and browsing web sites over the years, I have compiled a list of the most common English grammar mistakes by web authors. Here they are in Letterman (reverse) order.

10. Who, which or that?
"Who" (or "whom") refers to persons. "Which" refers to animals or things, never to persons. "That" can refer to either persons or things.
Examples of correct usage:
The girl who was hungry.
The dog which bit the mailman.
The bus that goes to the station.
9. Anyone vs any one
"Anyone" means "any person," not necessarily a specific person. It could refer to multiple people simultaneously.
As two words, "any one" refers to a single person.
Examples:
Anyone can download my software. But a single-user software license can only be used by any one user at a time.
8. Commonly misspelled words
All right
Dependable
Independent
Recommend
Responsible
Separate
7. Don't put punctuation at the end of a URL
While not technically an English grammatical error, don't put a period or anything immediately after a URL reference. Doing so will usually invalidate the URL. You might call this an internet grammatical rule.
Place the punctuation after the closing anchor tag of the link.
Example: {note that the anchor tags are not actually used so you can see the syntax.}
My URL is {opentag} HREF="http://www.kemptonsmith.com">www.kemptonsmith.com{closetag}.
6. Software not softwares
"Software" can be singular or plural. Never use "softwares."
5. Do the quotes go after or before the period?
Put quotation marks after a period or comma. Put quotes before a colon. Put quotes after a question mark unless the entire sentence is a question. This is a US English standard. British English usage can differ.
Examples:
He asked, "Are you hungry?"
She replied, "Yes."
Did she say, "Yes"?
4. There, their, or they're
"There" is used in two ways. It can specify a place. It can also be used as an expletive or empty word to start a sentence.
"Their" is used as a possessive form of "they."
"They're" is short for "they are."
Examples:
There are nine planets in the solar system.
The two boys raced their bikes.
They're both tired after riding so far.
3. Overuse of Powerful
Too many developers describe their software as, "XXX Software is powerful, easy-to-use, ... ." I searched download.com and found 2149 descriptions or titles of software containing the word "powerful."
Powerful has several meanings, and usually refers to how effectively something is performed, as in muscular. A car with 450 horsepower is clearly more powerful than one with only 200 horsepower. But what is powerful software? If you mean feature-rich (like Adobe Photoshop), then say so. If your software does only one thing, but it does it completely or thoroughly (like CounterSpy), then say so. But please, no more powerful software.
2. Site or sight
A "site" is a location or place.
"Sight" refers to your sense of vision; not to a web site.
Examples:
A web site is a place on the internet that you visit with your browser.
A beautiful sunset is a marvelous sight.
And, finally, the most common English blunder by web authors is:
1. Its or It's
The possessive form of "it" is "its," not "it's." Use "it's" only when it means "it is." Unless you can replace "it's" with "it is," use "its." Never use "its'."
Examples:
It's raining today.
The dog wagged its tail.