Yahoo has posted that Yahoo Search Ads are now limited to 70 characters descriptions for their advertising clients. Longer descriptions will be cut off in US results. Michael Mattis of Yahoo said “The optional 190-character long descriptions may still be displayed on some of our distribution partners’ sites.”
In April 2007 he wrote about the forthcoming changes in description. “We’re doing this (to quote myself) because ‘we’ve found that ads written more concisely give users a better experience and perform better for advertisers’.”