Do we really need e-readers? As the world is overrun by bigger smartphones and smarter tablets, you might think not. But the single-purpose gadgets seem to be holding their own. This year, in fact, the number of e-reader owners will surpass 86.3 million, according to a new forecast from eMarketer. If accurate, that will represent an annual growth rate of 3.5%.

Not to be outdone by Periscope and similar apps, Facebook is going all in with its video-streaming feature, Live. The social giant only began testing live video-streaming late last year. Then, last month, it expanded the ability to share live video to iPhone users in more than 30 countries. Now, all domestic Android users are being invited to join the party, while plans are already in place to bring in Android users around the world.

Simply liking things is passe now that Facebook can accommodate a larger range of simple emotional reactions. The new reactions feature has gotten some buzz this week, allowing users to select from a host of emojis in place of a "like" on posts that show up in their news feeds.

Yesterday, I marveled at Instagram's age-defying growth. Today comes word that the network has surpassed 200,000 advertisers. For the Facebook unit, it's a point of pride. But I wonder whether Instagram's aggressive monetization strategy poses the greatest risk to its popularity.

No spring chicken, Instagram's growth is supposed to be maturing. For now, however, the network seems to be defying the laws of aging. This year, 89.4 million U.S. consumers will log on to Instagram at least once a month -- representing 34.1% of all mobile users, eMarketer expects. More to the point, 51.8% of social network users will use Instagram -- surpassing the 50% mark for the first time -- by 2017.

Call it wellness or sheer superficiality, but beauty and fitness sites are dominating consumers' smartphone time. In fact, mobile traffic now constitutes 67.25% of the beauty and fitness sector's overall activity, according to new findings from SimilarWeb.

With the help of a tech startup named Shine, European mobile carrier Three is planning to block what it calls "excessive, intrusive, unwanted or irrelevant" ads on its network. The move sets the stage for a battle between carriers -- which argue that the ads hog excessive amounts of bandwidth -- and big ad providers like Google.

The FBI wants Apple to build a custom piece of software that will allow the Bureau to unlock a specific iPhone (used by terrorists) through brute force. Apple rebutted by issuing a public letter explaining that such a piece of software would be a genie that couldn't be put back in the bottle. It's a case that has echoes of the Patriot Act, which in part leveraged the 9/11 attacks to expand governmental surveillance capabilities -- eventually leading to the bloated NSA programs outed by Edward Snowden several years ago.

Tumblr's usership is already plateauing, and this will mark its last year of double-digit growth.

Get ready for a major turning point in the world of ecommerce and mobile marketing. Next year, more than half of all domestic digital consumers will use a smartphone to complete at least one purchase. That's according to a new eMarketer forecast, which expects 95.1 million Americans ages 14 and older -- or 51.2% of digital buyers -- to tap the "buy" button on their phones.