Despite dominating market share (attaining a peak of 90% in mid-2004), this version of Internet Explorer has been widely criticized for its security issues and lack of support for modern web standards, making frequent appearances in "worst tech products of all time" lists, with PC World labeling it "the least secure software on the planet.

"[2] In 2004, Mozilla finalized Firefox to rival IE6, and it became highly popular and acclaimed for its security, add-ons, speed and other modern features such as tabbed browsing.

In addition, IE6 added DHTML enhancements, content restricted inline frames, and partial support of DOM level 1 and SMIL 2.0.

Other new features included a new version of the Internet Explorer Administration Kit (IEAK) which introduced IExpress, a utility to create self-extracting INF-based installation packages,[11] Media bar, Windows Messenger integration, fault collection, automatic image resizing, and P3P.

[citation needed] On March 4, 2011, Microsoft urged web users to stop using IE6 in favor of newer versions of Internet Explorer.

[citation needed] The security advisory site Secunia reported 24 unpatched vulnerabilities in Internet Explorer 6 as of February 9, 2010.

These vulnerabilities, which include several "moderately critical" ratings, amount to 17% of the total 144 security risks listed on the website as of February 11, 2010.

[17] On June 23, 2004, an attacker used two previously undiscovered security holes in Internet Explorer to insert spam-sending software on an unknown number of end-user computers.

[18] This malware became known as Download.ject and caused users to infect their computers with a back door and key logger merely by viewing a web page.

Tools such as DropMyRights[19] are able to address this issue by restricting the security token of the Internet Explorer process to that of a limited user.

Art Manion, a representative of the United States Computer Emergency Readiness Team (US-CERT) noted in a vulnerability report that the design of Internet Explorer 6 Service Pack 1 made it difficult to secure.

He stated that: There are a number of significant vulnerabilities in technologies relating to the IE domain/zone security model, local file system (Local Machine Zone) trust, the Dynamic HTML (DHTML) document object model (in particular, proprietary DHTML features), the HTML Help system, MIME type determination, the graphical user interface (GUI), and ActiveX.

[21] In response to a belief that Internet Explorer's frequency of exploitation is due in part to its ubiquity, since its market dominance made it the most obvious target, David Wheeler argues that this is not the full story.

[22] As a result of its issues, some security experts, including Bruce Schneier in 2004, recommended that users stop using Internet Explorer for normal browsing, and switch to a different browser instead.

[23] Several notable technology columnists suggested the same idea, including The Wall Street Journal's Walt Mossberg[24] and eWeek's Steven Vaughan-Nichols.

[31][32][33] Nonetheless, IE6 continued to maintain a plurality or even majority presence in the browser market of certain countries, notably China[34] and South Korea.

Developers often resorted to strategies such as CSS hacks, conditional comments, or other forms of browser sniffing to make their websites work in IE6.

[48] With media queries unavailable, responsive widths could be implemented to a limited extent by wrapping elements inside tables.

[50][51] Several campaigns were later aimed at ridding Internet Explorer 6 from the browser market: With the increasing lack of compatibility with modern web standards, popular websites began removing support for IE6 in 2010, including YouTube[6] and their parent company Google;[7] however large IT company support teams and other employers forcing staff to use IE6 for compatibility reasons slowed upgrades.

ActiveX support remains in Internet Explorer although access to the "Local Machine Zone" is denied by default since Service Pack 2.