It's been the better part of a week since Microsoft revealed that virtually every single version of its Internet Explorer web browser was vulnerable to a particularly nasty attack, one so scary that U.S. Homeland Security recommended people not to use the browser until the hole is patched.

Now, it is: Microsoft will deliver the patch for all versions of Internet Explorer on Thursday (including Windows RT). Windows XP, which Microsoft discontinued support for on April 8, will get a patch, too. If you have automatic updates turned on, you won't need to take any action to get the security patch.

The news should cheer consumers, Homeland Security and the millions of stubborn Windows XP users around the world.

This does not mean Microsoft is turning Windows XP support back on, though. From the Microsoft blog post on the patch:

"Windows XP is no longer supported by Microsoft, and we continue to encourage customers to migrate to a modern operating system, such as Windows 7 or 8.1. Additionally, customers are encouraged to upgrade to the latest version of Internet Explorer, IE 11."

Is it too late?

Even as the fix slides into computers around the world, questions remain about Internet Explorer's future viability in the marketplace. There was, to be certain, a whisper campaign about this marking the beginning of the end. However, some industry experts don't see this as a watershed moment for the once-dominant web browser.

"I don’t expect a huge backlash on Internet Explorer’s market share," said Gartner security analyst Lawrence Pingree. "In fact, I think this helps drive adoption of upgrades to Windows 7 from XP."

Pingree suggested that Homeland Security probably made its recommendation because it was worried that Windows XP wouldn't get a patch, which would leave users without a choice.

Still, industry watchers know Microsoft needed to move fast. “Browsers are essential to the web, and if it becomes vulnerable people will lose trust in it," said Tim Bajarin, the president of Creative Strategies. "Microsoft and all browser vendors must be more vigilant and deal with any holes fast and judiciously."

Is Internet Explorer safe?

This most recent security black eye may have distorted Internet Explorer's actual record on security, Pingree suggested.

"Some of the studies I’ve seen actually indicate that IE has some of the best security of all the browsers," he added.

He was likely referring to a recent study from NSS Labs that put Internet Explorer on top for blocking what are known as social engineering attacks. These are primarily non-code-based attacks that rely on consumer naiveté and gullibility to trick them into clicking on links and opening dangerous emails. Internet Explorer reportedly blocked 99% of these attacks, while Google's Chrome caught roughly 71%.

Microsoft remains committed to the browser, versions of which exists across its entire product line of desktop and mobile operating systems. The company most recently introduced Internet Explorer 11.

Not-so-global dominance

Once the leading web browser, Internet Explorer has lost significant ground in recent years, mostly to Google's Chrome. Now, at roughly 58% of global browser usage market share, it has only the slimmest margin over competitors, according to Net Applications.

In the U.S., that number is even smaller. As of March of this year, Net Applications reported Internet Explorer had 53.54% usage. There's also the reality that web surfers rely on increasingly on mobile devices; as of late last year, Microsoft's mobile OS accounted for just 3.1% of the market.

Making the switch

Pingree insists consumers won't switch browsers because most don't even know how to do it — but in reality, consumers are switching already.

Recent earnings reports from both Twitter and Facebook indicate that most of their revenue and/or activity is coming from mobile users who rarely surf the web on desktops and laptops.

As we ease into the fourth year of our post-PC world (the beginning marked by the introduction of the iPad in 2010), that trend will continue. Many millions still own and use desktop computers every day, but they're living mainly in mobile.

[Ed Note: An earlier version of this story said mobile versions of IE were affected, as well. Although the tablet OSes Windows RT and Windows 8.1 RT are affected, the mobile OS for Windows Phone is not.]