The last article I wrote about new Yahoo! (NASDAQ: YHOO) CEO Marissa Mayer was shortly after she spoke at the Fortune Most Powerful Women's conference on Dec. 4. Meyer, after her 30-minute dialogue with Patricia Sellers, provided some rare insight into her plans for the $23 billion online leader.

The overriding message Mayer imparted at the FPMW conference was the necessity for Yahoo! to become a seamless provider of content and services for the exploding, worldwide mobile computing population. Though not quite as emphatic, Mayer also mentioned having Yahoo! become a more technologically savvy destination portal. Looking back, it's clear that Mayer was laying the groundwork for today's news.

The old, and new, Yahoo! email experience
It's a gross understatement to say the revamping of Yahoo!'s email service, announced today on its blog by none other than Mayer herself, was needed. I'm a prime example. While my desktop (remember those?) isn't exactly tied to a T-1 line, it's not bad, either. Yet, I consistently find myself waiting for my email account to load, move from page to page, and even log off.

Yahoo!'s new email promises to be cleaner, with "fewer distractions" than its old version. Though finding accurate email account total users is difficult, according to Email Marketing Reports, Google (GOOGL -1.68%) Mail has 425 million, compared with approximately 350 million for Yahoo!

Why? Google doesn't have an endless number of pictures, ads, and assorted other goodies, all of which slow the service down. What Google's figured out, and Yahoo! is realizing, is the value of all those email user account's lies in the analytics, not inundating them with content in the hopes of increasing ad revenue.

Every bit as important as the new, cleaner experience is that the new Yahoo! mail has, according to Mayer, "a consistent look and feel, across mobile devices." If your mobile phone or tablet is running Google's Android, Microsoft's Windows 8, or Apple's iOS, doesn't matter, Yahoo! now has an app for that.

What it means
As valuable as providing users with a better experience is, email or otherwise, Mayer's unveiling of the new Yahoo! mail goes beyond its functionality. She doesn't speak often, but when she does, she delivers on what's promised. Mayer's FMPW interview, particularly the emphasis on better mobile compatibility and the development of relevant apps, was clearly a precursor to today's Yahoo! mail announcement; that's what CEOs do.

But beyond Mayer's salesmanship, Yahoo! knows it's in for an uphill battle. Facebook (META -4.55%) continues expanding on its advertising arsenal with new tools for its ad customers -- the discussions to purchase Microsoft's Atlas service is evidence of that. AOL (NYSE: AOL) is also making strides in its efforts to become a content-rich, destination site, just like Yahoo! The Huffington Post, along with AOL's video service On Network, aren't just popular; they generate significant revenue.

The fight is on, and Mayer is starting to deliver the solutions Yahoo! needs as its stock price bumps up against 52-week highs. The new Yahoo! mail? It's a must-have, and I'm looking forward to a better user experience, but that's not what today's announcement is about. The new mail is about the fact that Yahoo!, and Mayer, are starting to deliver.