It was almost a year ago that a subway ride turned Violet Kittappa into an activist.

She was on a crowded Queens-bound W train when she noticed a middle-aged man inching toward her. She tried to concentrate on her book and ignore him, when she felt a nudge on her leg. The man was breathing heavily, and his face was contorted. When she looked down, she realized that he was rubbing against her.

“This is when I flip out,” Ms. Kittappa wrote shortly afterward on ihollaback.org, a Web site that encourages women to post their accounts of harassment and abuse as part of a campaign to end practices that are seldom discussed but that many women say are pervasive.

As a movement, it seems to be gaining traction. The City Council’s Committee on Women’s Issues held its first hearing on street harassment last month. At the same time, technology has enabled women to document what previous generations could not. They can now take photographs of the men who accosted them and publicize the pictures, which allows women to assist the police or embarrass those who have harassed them.

Now Hollaback  which in this case refers to the act of responding to harassment on the Web  is expanding its service to mobile devices. This week, the group is releasing an iPhone application that allows users to report harassment in seconds. The data is automatically mapped, and a follow-up e-mail from Hollaback asks for a more detailed account of what happened.