I'm Carl Kintanilla. You're listening to CNBC's Tech Check. Our show is live weekdays at 11 a.m. Eastern. Listen in.

Good Tuesday morning.

Welcome to a big hour of tech check.

I'm Carl Kintanilla with John Ford and Julia Borsden.

Today, the Internet's third rail and the stock dividing Wall Street.

Jason Kalakannis joins us for debate on whether Facebook is investable here. Then, what's today's better opportunity in tech, both Square and Airbnb getting some upgrades, but which one belongs

in your portfolio? Later, Piper. I got some new money ideas in the cloud, some bullcases on

Salesforce, Twilio, and Coupa this hour, Julia. But we're going to start with Facebook.

The stock is down more than 2% today.

Now down 16% since the start of September and one of the biggest laggards on the NASDAQ 100 this morning.

And there's been a fire report just out from Bernstein.

It calls the stock, quote, the internet's third rail, posing the question,

is Facebook investable? The analyst behind that note is Mark Schmullick, who joins us now. Mark,

thanks for talking to us today. Now, you have a buy rating on Facebook, despite laying out

all of these various challenges, including challenges targeting advertising, regulatory

overhang. Why do you have a buy

rating on this stock yeah um you know there's certainly a lot going on with uh you know with

facebook right now and it's one of those kind of emotional topics kind of just like religion and

politics and you know aside from i guess a lot of the the rhetoric around the name there's

obviously a lot of fundamental questions with the the name there's obviously a lot of

fundamental questions with the idfa impact coming in this quarter um regulatory overhang engagement

questions um you know why i continue to like it is despite all of the noise as we look ahead into

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