Facebook today announced its grand plan to make its news feed into "the best personalized newspaper," in CEO Mark Zuckerberg's words, where users can peruse streams consisting entirely of photos, events, music-related content or of posts from brands or public figures they follow.

The social network also characterized the redesign of its core product as a bid to utilize more of the real estate within a Facebook page (news feed in its outgoing form took up only 40% of the screen) by making posts larger. Friends' photos and ads that show up in news feed alike will be bigger and more eye-catching.

The updates start rolling out for desktop today and for mobile devices in the coming weeks.

Here are five early takeaways.

Ads are (much) bigger. Yes, everything else is bigger too. But creatives may now have a canvas they can sink their teeth into. A look at this reporter's newly reformatted news feed showed an ad with a video of the trailer for the upcoming "The Hangover Part III" that took up almost the whole height of her laptop screen. Even Facebook's original ads that don't contain any rich media on the right-hand rail look bigger.

The higher engagement that larger ads are bound to bring will please marketers. But there's always a risk of ads being annoying to users, who now have to scroll down more to see the content they're most interested in.

"If it's not elegantly executed, you're going to see consumer backlash," said Gian LaVecchia, MEC's digital lead.

Consumer engagement in new feeds is a question mark. Mr. Zuckerberg was emphatic that there's been a great deal of consumer demand for a better way to consume filtered content like photos and music (a feed that in its current incarnation includes posts from bands that users and their friends have liked, as well as songs friends have listened to on services like Rdio and Spotify). But it remains to be seen how high a percentage of users will have a use for it.

"I really wonder how many people are going to take an effort with all of those," said eMarketer's principal analyst Debra Aho Williamson.

Facebook users with access to the redesign can see the new feeds by clicking on a tab on the right-hand corner of their screen. Initially, the new feeds won't have ads, but Facebook execs confirmed they're coming.

But if the new feeds do take off, it could make it harder to reach fans on Facebook. If the feeds end up engrossing a wide swath of users, it could mean that the Facebook audience becomes more fragmented. Which could exacerbate the frustration of brands who have already observed the organic reach of their posts declining due to algorithm changes.

So if users spend significantly less time in their main news feed, where posts from brand marketers are most likely to surface, it could become necessary to buy back the lost reach.

Users might also conceivably find the option to filter down to see only posts from their friends to be more tantalizing than the main news feed.

"If people continuously opt for this filter, it will greatly diminish brand engagement opportunities outside of paid reach," said Chris Copeland, CEO of GroupM Next.

There won't be algorithmic changes. Users will see just as much of the content posted by brands they follow in the main news feed as they were prior to the change, according to a Facebook spokeswoman.

Potential sponsorship opportunities down the road? If the music feed winds up getting a lot of usage, it's not a leap to imagine that an entertainment-focused brand like Pepsi would be interesting in sponsoring it. While Facebook currently has no such plans, VP-product Chris Cox said the idea of news-feed sponsorships has been discussed.

Organic 's VP-strategy and planning Anna Banks said that sponsorships could be a less intrusive way for brands to market on Facebook, with less risk of irritating users.

"It could move to [brands] sponsoring parts of streams or feeds, and then eventually to them owning streams," she said.