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The Final Word on Punctuation. Period.

When it comes to keyword generation, I tend to follow the general rule that more is better. More variations, more match types, more misspellings, more modifiers, etc. However, as we all know, there are always exceptions to the rule.

As it turns out, more is not the best policy when it comes to using punctuation and symbols in keywords. In fact in most cases, it’s simply not allowed.

Google, MSN/Bing, and Yahoo! all have documented guidelines regarding the use of punctuation and symbols in keywords. Some are more clear-cut than others and all three vary.

It’s important to point out the subtle differences:


Google explains their policy in terms of Valid Symbols, Ignored Symbols, and Invalid Symbols:

I. Valid Symbols: The AdWords system only recognizes two kinds of symbols in keywords: ampersands (&) and accent marks (e.g., á).

According to this rule, the following terms would be considered different keywords:

bed and breakfast ≠ bed & breakfast
sidewalk cafe ≠ sidewalk café

II. Ignored Symbols: AdWords will allow you to add keywords containing periods or dashes, but the punctuation will be ignored (more on this later…)

For example the following keywords are considered identical:

T-rex = T rex
Fifth Ave. = Fifth Ave

If your account contains more than one equivalent keyword, such as in the examples above, only one of the keywords will trigger an ad per search query. Google recommends deleting keyword duplicates to make ad groups more manageable.

III. Invalid Symbols: AdWords will give you an error message if you try to add keywords containing the following symbols to your account:

! @ % ^ * () = {} ; ~ ` <> ? |

And be aware that if you include a comma in your keyword, the system will treat the term as two keywords. For instance, if you try to add flowers,plants, you’ll actually add the keywords flowers and plants to your ad group.


MSN adcenter uses a process called normalization to identify and flag duplicate keywords. Certain symbols, punctuation, and uses of capitalization are normalized (translated differently by MSN) and others are not.

The following key helps illustrate what’s normalized and what’s not:

What IS Normalized


What is NOT Normalized


Yahoo! :
(http://help.yahoo.com/l/us/yahoo/ysm/sps/ols/2006002_keywords.html )

“Understanding Keyword Variations: It is not necessary to enter multiple variations of your keywords. Your primary keyword (meaning a keyword that is singular, non-punctuated, non-hyphenated, spelled correctly and without words such as “a,” “the,” “of” and “for”) is automatically matched to common misspellings, singular/plural combinations, and other variations. If you enter multiple versions of a keyword as described above, the display will show only the primary keyword.”

So there you have it, the three are similar, yet just different enough that you will need to re-read this blog at least eight more times before you can confidently speak to the differences of the use of punctuation and symbols in keywords at your next team meeting.

Now you know everything you need to know on the subject…or do you?

Remember Google? Well, when it comes to using periods (.) in keywords, it turns out that Google’s system is not so cut and dry. According to Google, periods are ignored symbols.

Therefore, fifth ave. = fifth ave

Okay, but what if the period falls in between letters, as in the case of acronyms like ‘u.s.a.’ or ‘n.y.p.d.’? I’ve been told that in that case, Google treats the period as a space.

Therefore, u.s.a. would equal u s a

I tested the concept by entering both variations into Google’s Traffic Estimator, and lo and behold, they are indeed treated the same. But what about ‘u.s.a’. vs ‘usa ‘(no spaces)? Interestingly, ‘usa’ without spaces is also equal to u.s.a. and u s a. Again, Traffic Estimator confirmed this:


Up until this discovery, I would have treated usa and u.s.a. as two completely different keywords, living in separate ad groups, with varying creative.
Not the best approach, according to Google. To do so would cause the two keywords to compete against each other. One ad group would subsequently perform worse than the other, bringing overall performance down. Thus, improving keyword efficiency in regards to punctuation requires that you test several variables across each specific search engine.

And that’s the final word on punctuation… until the search engines modify their policies.  Although many of these editorial guidelines are straightforward, others leave plenty of room for interpretation.  So if you’re a punctuation enthusiast like me, please share your experience and let us know what other quirks you have come across.

About Mary Hayes

As a Creative Editor, Mary Hayes brings more than 13 years of marketing experience to TSA’s SEM group. After 9 years in print publishing, she dove head first into the world of SEM and hasn’t looked back since. An accomplished copy writer and content editor, Mary has experience with several different industries, including healthcare, medical devices, pharmaceuticals, cosmetics, medical research, manufacturing, and more. A native of Maryland and graduate of the University of Maryland, College Park, Mary proudly considers herself a true California girl.