Google recently announced a new keyword targeting feature on the Inside AdWords blog. Broad match modifier is a middle ground between broad and phrase match. The intent is to take phrase match and make it a little broader and broad match a little more controlled.
Implementing this feature works similarly to the standard broad, phrase and exact match keywords used today. Instead of the brackets or quotation marks you use a plus (+) sign. The plus sign modifies the word it is attached to so that it must appear in the searcher’s query exactly as is or a close variation. Close variations include misspellings, singular/plural forms, abbreviations and acronyms, and ings (like “floor” and “flooring”).
Today you may have the broad match keyword of black hat. As a standard broad match keyword this can match multiple variations such as black caps, gray hats or black baseball hat. If you had that same word as a phrase match it may match on things like midnight black hat or black hat for baseball. With the new broad match modifier feature you can narrow down those broad matches and expand the phrase matches.
Enter your keyword as +black hat (Be sure there are no spaces between the + and modified words, but do leave spaces between words). The resulting matches in this case could be black cap, fancy black dress hat, blck hat or black ski caps. The plus sign in front of black forces black to be in the searcher’s query. If you were to enter your keyword like this, +black +hat, your matching results could be things like black hatt or black baseball hat or any variation as long as both black and hat are queried.
Note that broad match modifiers are designed for adgroups that contain mostly phrase and exact match words. If you are mostly bidding on broad match adding the modifiers could result in a significant decline in clicks and conversions.