When Facebook(s sb) acquired popular messaging service WhatsApp for an eye-popping $19 billion, other app makers took notice. And, fearful of missing out on a maturing market for “social” apps, some of those companies are trying their hand at what Silicon Valley types call “growth hacking” — or what the average person would call text message spam.

Those are the observations of Cathal McDaid of AdaptiveMobile, a network security firm that has produced a report naming some of the worst offenders for growth-hacking. Common tactics include getting users to blast everyone on their phone contact list with an invitation to try the app, or “alerting” a user’s friends whenever they do something ordinary like post a photo.

“It a two-part problem. There’s a tolerance for it, and a desperation to catch WhatsApp…It’s a very aggressive way of spamming,” Cahill told me, adding that some app makers can’t restrain themselves when they see their competitors resorting to such tricks.

While some social gaming…