The release contained many new features not found in Firefox 1.5, including improved support for Scalable Vector Graphics (SVG) and JavaScript 1.7, as well as user interface changes.

The Gecko 1.8.1 browser core continued to receive patches for projects such as Camino, K-Meleon, and SeaMonkey, even after official Firefox releases had ceased.

By 2011, the 1.8.1 core had become obsolete, as major websites dropped support for it[15] by employing newer technologies for presentation and complex scripting.

[16][17] The latter can be resource-intensive with the older core, and users stuck with it should use NoScript[18] to avoid problems with scripts that take too long to process (at the cost of losing some or all site features beyond basic functionality).

Nevertheless, there is still a very large number of websites that are freely usable and navigable with Firefox 2.0 or equivalents, alone because many of them must still support other older browsers, like Internet Explorer 6 or IE7.