On January 1 of next year, Google Maps
will institute a fee for users who exceed a limit of 'hits' per day. This will most likely affect sites such as travel discount companies.
From the article:
"We understand that the introduction of these limits may be concerning," said Thor Mitchell, product manager of the Maps API at Google.
"However, with the continued growth in adoption of the Maps API, we need to secure its long-term future by ensuring that even when used by the highest-volume for-profit sites, the service remains viable."