Abbreviated as IE according to AbbreviationFinder, Internet Explorer saves temporary Internet files to allow faster access (or offline access) to previously visited pages. The content is indexed in a database file, known as Index.dat. The multiple files that exist are different content indexes, visited content, RSS, Autocomplete, visited web pages, cookies, etc.
Before IE7, cache cleaning was used to clear the index, but files were not removed. This feature was a potential security risk for both individuals and businesses. Beginning with Internet Explorer 7, both the index of entries for files and themselves are removed from the cache when cleared.
Internet Explorer is fully configurable through Group Policy. Windows Server domain administrators can apply and enforce a number of settings that affect the user interface (for example, disable menu items and individual configuration options), as well as security features such as file download, zone settings, by site settings, ActiveX control behavior, and others. The configuration can be established for each user and for each machine. Internet Explorer also supports Integrated Windows authentication.
Internet Explorer uses zone and site group-based security over certain conditions, even if it is a web-based Internet or intranet, as well as a whitelisted user. Security restrictions apply for each zone; all sites in a zone are subject to the restrictions.
Internet Explorer 7 includes a phishing filter, which restricts access to fake sites unless the user overrides the restriction. Internet Explorer 8 also blocks access to sites known to store malicious software. Downloads are also analyzed to see if they are known to be infected.
In Windows Vista, Internet Explorer by default runs in what is called Protected Mode, where the privileges of the browser itself are highly restricted. You can optionally navigate outside this way, but it is not recommended. This also limits the effectiveness of the add-on privileges. As a result, even if the browser or any add-on is compromised, the damage it can cause is limited.
Patches and updates for the browser are released periodically and are available through the Windows Update service, as well as through Automatic Updates. Although security patches continue to be released periodically for a wide range of platforms, the latest features and security enhancements are released for Windows XP SP2 and later-based systems.
Internet Explorer has been the subject of many security vulnerabilities and concerns: most spyware, adware, and computer viruses are transmitted through the Internet by exploiting flaws and flaws in Internet Explorer’s security architecture, sometimes requiring nothing more than just viewing a malicious web page to install the virus themselves. 
A wide series of security flaws that affect IE do not originate in the browser itself, but in the ActiveX used by it. Because add-ons have the same privileges as IE, flaws can be as critical as a browser flaw. Other browsers that use NPAPI as their extensibility mechanism suffer from the same problems.
The adoption rate of Internet Explorer is closely related to that of Microsoft Windows, as it is its default web browser. Since the integration of Internet Explorer 2.0 with Windows 95 in 1996, and especially after version 4.0, adoption has been very accelerated: from less than 20% in 1996 to around 40% in 1998 and more than 80% in 2000. This effect, however, has recently been called the “Microsoft monoculture”, by analogy to problems related to the lack of biodiversity in an ecosystem.
A CNN article noted at the launch of Internet Explorer 4 that “Microsoft’s Internet Explorer has made strides and various estimates by putting its browser market share at 30 to 35 percent a year ago.”  In 2002, the Internet Explorer had almost completely replaced its main rival.
After having fought and won the browser wars of the late 1990s, Internet Explorer gained almost total market dominance. After having reached a peak of around 95% during 2002 and 2003, its market share has declined at a slow but steady pace. This is mainly due to the adoption of Mozilla Firefox. Statistics indicate that it is currently their most important competition.
Firefox 1.0 has overtaken Internet Explorer 5 in early 2005 with Firefox 1.0 by approximately 8 percent market share. An article points out in the release of Internet Explorer 7 in October 2006, “IE6 has the largest share of the market with 77.22%. Internet Explorer 7 has risen to 3.18%, while Firefox 2.0 was at 0.69%. ” in November 2006, with approximately 9% market share. Firefox 2.0 outperformed Firefox 1.x in January 2007, but IE7 didn’t outperform IE6 until December 2007.
In January 2008, their respective versions stood at 43% IE7, 32% IE6, 16% Firefox 2, 4% Firefox 3, and Firefox 1.x and IE5 by less than half of 1 percent.
According to Marketshare, all versions of Internet Explorer dominate 59.25% of the market while w3schools gives it 33.4%, well below the 46.4% given to Firefox. It should be noted that both calculations are made based on data collected on the traffic in their own networks or websites that use their services, therefore not being representative samples from the formal point of view of statistics.