Then Mr. Gawley revealed a surprise: Gmail will begin allowing advertisers to use images. For example, an e-mailed offer for a ski package showing a skier on the slopes could be accompanied by an ad on the right side of the screen, showing a competing offer, replete with another skier coming down another slope.

Mr. Gawley said the image used in the ad would be static, not animated, and would be used only in cases where the e-mail message itself showed images.

Gmail has never permitted anything but text ads, so this will be a major change for its users. Mr. Gawley acknowledged this and emphasized that the company was moving slowly before it introduced images as an ad option. “Even though we’ve seen positive results on the advertising side, we want to make sure that users are not alienated,” he said. “With this one, we want to be extra cautious.”

Hotmail and Yahoo Mail have long used not only image ads but also animated ones. Last week on Hotmail, I saw two different versions of an ad titled “Return to School With a Grant.” One displayed cartoon school buses going round and round a figure-eight track. The other showed a woman in a leotard, with a cap on her head and an inclination to jump up and down every few seconds, apparently ecstatic that she had just graduated.

A spokeswoman for Microsoft said Hotmail had recently reduced the number of image ads per page to one from two, as part of a “consumer-first approach.” She also said the company had eliminated text-only ads entirely from Hotmail in order to “provide a cleaner user experience.”

For me, though, a clean user experience is a text-only advertisement of just a few words — it beats images or anything else. Google’s text ads are the modern equivalent of tiny text ads that daily newspapers in the 19th century carried on their front pages. James D. Norris, an emeritus professor of history at Northern Illinois University, described those ads as saying “nothing more than ‘we have such-and-such goods in stock.’ ”