Firefox is still gaining popularity - that's a given. And as more people use FF, the more people are coming across the trendy browser's extensibility. The latest of these new extensions is becoming wildly popular amongst 'Foxers' in the know, as it allows users to tweak how the browser renders the page being displayed. It has however got the Security community's knickers in a knot. News.com gives the low down: A new Firefox extension that lets people customize their experience of the sites they visit is stirring excitement among Web surfers and consternation among security experts. Greasemonkey, a new extension to the Mozilla Foundation's Firefox browser, lets people run what's known as a "user script," which alters a Web page as it's downloaded. That capability has gained the extension an avid following of Web surfers who want to customize the sites they visit, removing design glitches and stripping sites of ads. But the extension comes with substantial security risks, and could stir trouble among site owners who object to individual, custom redesigns of their pages. More here, as long as GreaseMonkey lets it through.