Matthew Meola launched into his talking points haltingly.

“We’re concerned about this, um, bulk collection,” he said, rehearsing the message he planned to deliver to congressional offices. “We’re concerned it violates the Constitution.”

But the words became more fluid as he channeled his concern Friday about NSA surveillance, in preparation for a lobbying trip to Capitol Hill demanding closer scrutiny of the secretive agency. If the spiel didn’t come easily at first, well, he’s not a lobbyist. Like so many of the protesters turning out for this weekend’s Stop Watching Us march, he’s a tech guy: a computer scientist from Cambridge, Mass.

Oh, did you expect anti-tech folks — the tinfoil hat crowd, the off-the-gridders? Instead, it’s the super-techie community that has been agitated about the government’s power to collect and analyze our personal data — “people who care” about the issue “because they understand it,” said Chris Lewis, vice president of Public Knowledge, one of the event’s nonprofit-group organizers.

“This is probably the defining issue of a young generation of technologists,” said Matt Simons of ThoughtWorks, a software developer that is one of the weekend’s corporate sponsors. “If you’re not coming out on the right side of history, you’re in the wrong industry.”

Organizers hope to draw a couple of thousand protesters to the rally and march, set to kick off at 11:30 a.m. Saturday in front of Union Station before moving to the Reflecting Pool at the Capitol. Speakers will include Rep. Justin Amash (R-Mich.), former congressman Dennis Kucinich (D-Ohio), NSA whistleblower Thomas Drake and former Army Lt. Dan Choi, who is a gay-rights activist.

Hosted by a hodgepodge coalition that includes the American Civil Liberties Union and the Council on American-Islamic Relations as well as libertarian-leaning groups such as the Competitive Enterprise Institute and FreedomWorks, the Stop Watching Us organizers hope for a diverse crowd that includes the Internet-weary. No need to RSVP by name: Just show up! Don’t worry about those addresses they’re collecting from you — it’s just to let lawmakers know that an actual constituent has shown up; no other use for the data planned.

But it’s the Internet-savvy who represent the beating heart of the movement. At a training session Friday morning on the Hill, a few gray-haired activists and policy wonks stood out in a crowd dominated by the postgrad vibe — beards, glasses, shaggy hair — of techies on their day off from the cubicle farm.

“I have been personally disappointed I haven’t been able to rally my less-geeky friends,” said Vince Kane, 36, a shaved-head computer engineer for the Navy who lives in Northern Virginia.

Polls show a sharp increase in the number of Americans who are concerned about the government’s collection of Internet and phone data, ever since the June disclosures by NSA defector Edward Snowden — yes, another tech guy. Yet among his non-tech friends, Kane still senses complacency. “We have a culture of, ‘Oh, your information is out there already.’ ”

But the IT guys you call every time that weird prompt freezes your screen? They get the big picture. “We’re much more aware of it,” said Joseph Slade, 27, a lanky government contractor in glasses. “Twenty years ago, if they collected this information, they couldn’t do much with it.”

At the training session, policy veterans offered the geeks some tips for navigating their Hill meetings: Stay on schedule. Be succinct. Don’t be nervous.

Greg Nojeim of the Center for Democracy and Technology tried to put the fear of God in them. Even a simple gathering such as the one they were in, he said, could fall under the NSA’s scope. “This meeting shows a relationship between the people here, and our locations can be tracked by the phone we carry. It’s a really critical moment.”

He was preaching to the converted. Meola, 29, said that while he once feared that the government would use its power to target individuals based on religion or ethnicity, he realized later that it was much bigger. “What they’re doing is saying, we’re going to take all the data we can possibly accrue, and they look at whatever they want to look at.”

Most chilling, he said, is what the government can do these days with “metadata.” Which is . . . ? Stephanie Cleary, 27, made a try: It’s all the data about your data — where and when your Facebook photos were taken, and the information from your phone that’s still stuck on them somehow.

“I deleted all my photos,” said the Boise State postgrad, who got her communications masters’ with a thesis on privacy policies. “I don’t do updates. I don’t have a photo of myself. It’s the little things.”

Thought about signing off altogether? “I’m torn!” she said. “I love the Internet for its accessibility to so many things in the world. You do the Internet in the right way, it’s so great.”