*update*
I found some old browser extensions that enable memory of customized css for pages you visit. Stylish for Chrome and Firefox.
Redesign Your Favorite Sites
While checking into gmail and twitter yesterday morning I craved nothing more than a complete overhaul to their user interfaces. While these services hold the keys to my data, they've done an inadequate job of empowering each user to customize the way they observe and use it. I'm pseudo comfortable with these companies having access to my data, although I'd prefer to replicate important info to multiple servers under my control. Regardless of who has a copy of data we create or interact with, choosing how we see it is entirely up to us.
There's no need for fancy authentication or separate applications to modify the views to these sites. Modifying views within a browser is as easy as a few custom lines of JavaScript, jQuery, or CSS but most folks aren't comfortable with editing code. The solution is obvious, a true read write web interface. A visual site crafting tool is something I want and can build.
The idea of customized interfaces isn't novel
Several companies are pursuing adjacent products. Visual portals constructed by users in the vein of iGoogle, Netvibes and now Wozaik are a step in the right direction but are tuned towards guiding users through their sites. I don't want to go through an intermediary to see my Twitter variant. I'd like to visit Twitter.com and have a malleable design that remembers how I last left it. There could be many variants of site views enabling me to select one that best suits my purpose. Instead of clipping pieces of web sites and pasting them into multiple portals, I'd prefer to modify the appearance of existing sites, and have the browser remember the customizations whenever I visit them.
Suggested Implementation
My instinct is to go with javascript that is aware of a browser's mouse and or touch interface. The memory of newly modified JavaScript/CSS/HTML can be accessed through browser addons, and synchronized between browsers so designs could be customized once and browsed anywhere. An option to see the native site design would always be available as well as a history of changes. There is a market opportunity here to encourage more active interface crafters, and enable them to easily share and sell their designs.
Elegant Example of Repurposing Space
A great example of reconfiguring space is Rapportive's repurposing of ad space in gmail for aggregated information about a contact. Hold on a second, isn't Google losing ad revenue by giving up this space? There are new avenues of monetization with companies like Rapportive and LinkedIn, to create more client value and revenue from the space. It's up to these companies to navigate a solution that benefits all parties. As a gmail user for 5-6 years I admit to never clicking an ad within the interface, although I've clicked through many Rapportive informational links in just a couple of months.