Nivi has a great post on Greasemonkey, a Firefox browser extension which lets users add “user scripts” to any web page. The first example Nivi cites where prices from competitive booksellers can be introduced as pop-ups right into the Amazon.com shopping experience – this is a case that grabbed my attention.
Here’s a good paragraph that sums up Nivi’s analysis of the technical implications:
Greasemonkey lets you mash-up websites. It lets you extend and script websites and integrate that script right into the original site as if the designers had intended it to be there. It lets you use their web site, their data, their servers, their work to serve your purpose and function. There will soon be an army of hackers enhancing every site you use. Whether that site likes it or not.
Nivi points out some items that affect the ability of Greasemonkey to scale up (e.g., support for other browsers). I also imagine that given general spyware concerns within the industry, trust will be a factor that affects adoption. Finding the killer website extensions (e.g., for eBay, Amazon, news, blogs) may help Greasemonkey to penetrate beyond the early adopter and Firefox market. In any case, it will be interesting to see how Greasemonkey plays out over time.