Amazon Echo and Google Home were the breakaway hits of the holiday shopping season. But both devices -- and the voice technologies that power them -- have some major hurdles to overcome if they want to keep both consumers and software developers engaged. From a report on Recode: That's one of the big takeaways from a new report that an industry startup, VoiceLabs, released on Monday. For starters, 69 percent of the 7,000-plus Alexa "Skills" -- voice apps, if you will -- have zero or one customer review, signaling low usage. What's more, when developers for Alexa and its competitor, Google Assistant, do get someone to enable a voice app, there's only a 3 percent chance, on average, that the person will be an active user by week 2, according to the report. (There are outliers that have week 2 retention rates of more than 20 percent.) For comparison's sake, Android and iOS apps have average retention rates of 13 percent and 11 percent, respectively, one week after first use. "There are lots of [voice] apps out there, but they are zombie apps," VoiceLabs co-founder Adam Marchick said in an interview.