JEFFREY BROWN: And now part of our regular look at the campaign as it plays out in social media and on the Web.

Margaret Warner has that.

MARGARET WARNER: And we're joined again by Howard Kurtz from the website Daily Download. He's also "Newsweek"'s Washington bureau chief and host of CNN's "Reliable Sources." Daily Download's editor in chief, Lauren Ashburn, could not be with us tonight.

And, Howie, welcome back.

HOWARD KURTZ, "Newsweek"/CNN: Thank you.

MARGARET WARNER: So, in this final week or 10 days of the campaign, we have seen this frantic get-out-the-vote drive, people knocking on doors, making phone calls. What kind of last-minute messages are voters getting on their computers and their mobile devices?

HOWARD KURTZ: Campaigns pulling out the stops online.

On Twitter, for example, Lauren Ashburn got a direct message signed Barack Obama saying, use your Twitter influence to help us turn out the vote, so, using that media network to try to get people engaged.

The e-mails are coming fast and furious to potential supporters. I seem to get an e-mail from Barack Obama, Michelle. Joe Biden has been texting me lately. There's no escape.

But another interesting thing, Margaret, is I got an unsolicited anti-Obama text message from an anonymous source. And lots of other people in the Washington area got them on their mobile phones.

Mine said—there are a couple versions of this—seniors can't afford to have four more years of Obama budget cuts to Medicare. That's arguable. They're not really cuts.

But point is you don't know where it's coming from. A Virginia company is behind this. Some of its conservative clients are distancing themselves from having anything to do with these anonymous text messages.

MARGARET WARNER: Are the campaigns themselves using these methods to get out negative messages at this stage, or are they all positive?

HOWARD KURTZ: They are not all positive, by any means.

I mean, the campaigns have websites in which the...

MARGARET WARNER: No. Of course, yes.

HOWARD KURTZ: ...President Obama's people attack Mitt Romney and vice versa.

So it's a mix of trying to identify your supporters and get them to register, get them to tell their friends, get them to tell the people on Facebook, and also driving negative messages, sometimes snarky Twitter-type messages against the other guy, and using a technique called data-mining.

MARGARET WARNER: Well, tell us about that, because we had a couple interesting pieces this week that Hari did—and we did in conjunction with "Frontline" --about what sorts of information the campaigns collect on potential voters.

How extensively are the campaigns—is there any way to quantify how extensively they're using it?

HOWARD KURTZ: There is a company that has quantified it, according to a piece in The New York Times, and we can put the graphic up. It shows the number of tracking programs or surveillance programs that each campaign is using.

And here you see President Obama's campaign, 76 different tracking programs to follow what potential voters and supporters are doing online, compared to Best Buy 74—so more than a major retailer. Mitt Romney's campaign also playing at 40 different tracking programs.

And these are software programs, Margaret, that look at your browsing history. They can find out what kind of things you buy, whether you have any financial problems, your dating history. Just about anything you do online is now fair game.

We have become accustomed, I think, to seeing retailing giants do this.

MARGARET WARNER: Absolutely.

HOWARD KURTZ: But, in political campaigns, this is something new.

MARGARET WARNER: Now, does a voter know if they're being tracked?

HOWARD KURTZ: The average voter doesn't know. But if you are suspicious or curious, you can go to a free program called Ghostery and you can find out which...

MARGARET WARNER: Ghostery?

HOWARD KURTZ: Ghostery. Find out which—kind of like Ghostbusters.

MARGARET WARNER: Oh.

HOWARD KURTZ: Find out which company might be tracking you. But it's hard to avoid these days.

And I find it a little unsettling. Like, I understand I get served ads for a shirt company because I bought some shirts recently. But just because I went to Mitt Romney's website to check his position on something, I have now been getting Mitt Romney ads.

And in this New York Times story, somebody who's a fervent Barack Obama supporter, but went to Mitt Romney's site to look at something, is also getting these ads. So it's not always perfect in its targeting.

MARGARET WARNER: Do the campaigns have any way of knowing how effective all of this—you have been here now for months, you and Lauren, telling us about how they're using the social media.

Do you have any way of knowing how effective it's been?

HOWARD KURTZ: They can't know for sure, but there are several rough indications that this is working, which is why the campaigns are pouring so many resources into it.

For example, as we know, both campaigns have raised a lot of money online and through text messaging. It becomes easy to donate. You pick up your phone.

MARGARET WARNER: And that's easy to see.

HOWARD KURTZ: Sure. Registration, the Obama campaign in particular has made a major effort to register voters and try to match the turnout if it can of 2008.

And I think we were on here once talking about how 25,000 new voters had registered based on some piece of information or website that the campaign had put up.

And there are studies showing, Margaret, that people are more likely to be influenced by their friends and their Twitter fans and their Facebook followers because these are people they know, they trust, more so than some impersonal e-mail, mass e-mail sent out by a campaign.

So there are lots of signs it's working. What we don't know is how that will translate into actual voting behavior next Tuesday.

MARGARET WARNER: Yes, we have to hope that whoever is designing the exit poll questions, there's a question. You know, when they say, did you make your decision at the last minute or a week ago, if there's something, what most influenced you?

HOWARD KURTZ: That would be a gold mine.

MARGARET WARNER: Wouldn't it? It would, definitely.

Well, Howard Kurtz, thank you so much.

HOWARD KURTZ: Thank you.