By JP Mangalindan
March 14, 2012

FORTUNE — This year’s South by Southwest Interactive may be remembered just as much for what happened outside the halls of the Austin Convention Center as what happened in them. Here’s a look at the biggest news stories to come out of the five-day media free-for-all:

Homeless hotspots? Sometimes marketing results in iconic campaigns, and sometimes the result is something decidedly less savory, like “Homeless Hotspots.” BBH Labs organized the marketing campaign, which had several homeless Austin residents wearing Verizon (VZ) MiFi 4G cards and acting as Internet hotspots with shirts that read “I’m [first name], a 4G hotspot. SMS HH [first name] to 25827 for access.” In exchange for a donation, users received wireless Internet access. The ploy drew many surprised looks from passersby. And although the company says all proceeds go toward the participating homeless residents, their objectification for the technorati to cruise the Internet became a hot topic.

CNN in talks to buy Mashable. Reports emerged this week that CNN (TWX) is in “advanced talks” to buy the popular blog Mashable for $200 million. Mashable founder Pete Cashmore responded with a denial, stating that the “rumor going around on Twitter that Mashable will be acquired this week” isn’t true. (That doesn’t mean it couldn’t be acquired next week.)

MORE: At SXSW, shrugs over CNN-Mashable rumors

Instagram’s rapid growth. Instagram may not have been the first photo-sharing app of its kind, but it may be the most successful. Co-founder Kevin Systrom admitted during a panel that there are now more than 27 million users, with 67% of them having used the app just yesterday. Also: the long-awaited Android app is coming soon and in some (unspecified) ways apparently, puts the iPhone version to shame.

This year’s break-out app: Highlight.  The mobile app from CEO Paul Davison generated buzz even before the conference began. At its core, Highlight users are alerted about one another based on their location, the number of Facebook friends they have in common, and common interests. Although SXSW attendees tried using the app to meet new people — perhaps the most obvious use case scenario for an app like this — Davison told Fortune that Highlight’s focus is more about giving you more information about the people around you, alerting you if friends happen to be a few blocks away, or reacquainting you with people you met once or twice. “It’s a subtle distinction,” he said.

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Google+ is being used — so says Google. Despite recent reports that Google+ (GOOG) users spend a mere 3.3 minutes there a month, rendering it a virtual “ghost town,” engineering chief Vic Gundotra argued the service is one of the fastest growing the company has ever launched. Gundotra reported that 50 million individual users log onto Google+ each day, and 100 million users sign in at least once a month, with a lot of social network activity happening privately among users. (He didn’t however, specify how much time they’re actually spending on it.)

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