Roughly 70% of Snapchat users are women, the chief executive of the messaging app said at a closed-door Goldman Sachs conference Wednesday. Co-founder and CEO Evan Spiegel said Snapchat users are sending 400 million “snaps” a day on the service, where messages disappear after a few seconds, according to a person who was present at the meeting. He said half of Snapchat’s users have tried out “stories,” a feature the company introduced last month to link multiple messages together. The on-stage interview, titled “What Lies Ahead for Snapchat,” covered the two-year-old company’s plans after spurning a roughly $3 billion acquisition offer from Facebook. Snapchat has not disclosed its number of users. Spiegel was asked about user numbers Wednesday but declined to discuss them.