Everybody knows that the trend is toward applications that run in a browser as opposed to desktop applications. What I’m starting to see is an emerging trend toward specialized Web browsers customized to make it easy to deal with specific applications. The proximate cause for this post is MailPlane, an OS X desktop application built strictly to interact with Gmail, based on Safari. In other words, it’s a Web browser that only works with one Web site.

Why would you want such a thing? Jeff Atwood describes some of the reasons in his critique of tabbed interfaces. When you have multiple browser windows open, and multiple tabs open in each, finding the tab you were using to read your email can be painful. With MailPlane, I have an icon on my dock that’s associated with email, and I can quickly get to my MailPlane window by way of Quicksilver. It also has a lot of nifty interface features that I rarely use, mainly because I’m so accustomed to using Gmail in a regular browser window and relying on keyboard shortcuts. I’ve been using MailPlane for about a week, and it would be painful for me to go back to treating Gmail as just a Web application.

The reason I’m calling this a trend is other applications I’m seeing. The first was Pyro, a standalone application for using the Campfire chat application. There’s also eMusic Remote, a customized version of Firefox for the eMusic Web site.

There are also plenty of other applications like offline blog composition tools and Twitter clients that interact with Web sites via Web services, but those fall under a different category.

I think we have Microsoft to thank for these specialized Web browsers. They produced a browser that also worked as a component in other applications. I worked at a company where some developers created a version of Mosaic that ran as a plugin for a videoconferencing application back in 1995, but that project never saw the light of day.

The Web may be the platform of the day for deploying new applications, but I’m not ready to discard all of the advantages of the desktop in favor of doing everything in the limited environment provided by the Web browser. Specialized Web browsers are a good compromise.