Young tech companies have a lot of things to do. Signing up users and raising money are usually at the top of the list. Much further down? Data security. That neglect has recently come back to affect many hot new applications and web services, which makes these companies rush to improve their products after breaches and holes were discovered. Only days after the messaging service WhatApp was sold to Facebook for up to $ 19 billion two weeks ago, security researchers pointed out that--- despite the company’s claims to the contrary – WhatsApp had relaxed encryption and protection of personal information for its more than 400 million users. Jay Nancarrow, a Facebook spokesman, said, after the WhatsApp deal closed, one of the first things Facebook planned to do was to conduct an intense security audit of WhatsApp and its messaging service. “We always perform a thorough security audit and share security resources when we acquire a company,” Mr. Nancarrow said. “Security is always a top priority for us.” While bigger and more established tech companies like Facebook generally have teams contributed to security, they are still affected by the defects. In late February, for example, Apple acknowledged a mistake in its operating system that could let hackers tap into information in emails. And in many ways, mobile apps and services –which have been taking off most rapidly lately—face security challenges. The information at risk on mobile devices is often more personal than on desktop devices, because mobile devices now include things like digital wallet apps, location-tracking recommendation services, and photo-messaging apps.