A long time has passed since version 2.1 (9 months) when the last bigger improvements were published. I started a lot of improvements in the last couple of months, finally I had time to consolidate and polish them (oder at least some of them). If everything is working as expected only time will show - you can help me solve them by reporting bugs. Changes include: Keyboard Shortcuts, Grid Overlay, GPS Toolbox, URLs without #, OpenLayers 2.12 and some improvements on the server side.
There are some shortcuts to interact with the map, like Cursor-Keys for panning the viewport and PgUp/PgDown for zooming in and out. Find a full list of shortcuts in the Options.
In the Layer toolbox you can find a new overlay: 'Map Grid'. It shows a longitude/latitude grid on the map. It listens on keyboard shortcut 'g'.
Find the new GPS Toolbox under the stick figure. It shows data collected by the Browsers' geolocation API. It also shows a stick figure on your current location if available. Optionally you can enable, that the viewport should follow your location as you move.
With the new HTML5 standard, AJAX applications may change the current page location without reloading or modifying the anchor (after the #). This makes for prettier URLs. OpenStreetBrowser uses the History.js-library for compatibility between browsers.
OpenLayers, the software responsible for the map interaction, has been upgraded to OpenLayers 2.12.
In case you miss the Start Location Toolbox (which was the default toolbox to appear), it's functionality has been moved to the Options - you can choose which location/view OSB should choose per default. Instead, the Search Toolbox is opened by default.
In the background there's a daemon which is responsible for compiling changed categories, (re-)starting the tile renderer and keeping the database up-to-date (which is not happing right now). It's somehow more powerful right now :)
Unfortunately, my update script deleted all categories. Fortunately I had something like a backup of the newest version of all categories, but the history could not be restored. Sorry!