This tool downloads replication diffs from OSM Planet site, calculates statistics on changes and registers which 0.01-degree tiles were affected, and stores this in a MySQL database. A series of PHP scripts and a JS frontend are used to access that data.

You can check a working installation at http://zverik.osm.rambler.ru/whodidit/

Make a directory outside www root (for example, /home/?/whodidit) and place parse_osc.pl there. Then create mysql database with utf8 collation and grant a user right to create and update tables there. After that, create database tables:

./parse_osc.pl -h <host> -d <database> -u <user> -p <password> -c -v

Add the script to crontab:

6 * * * * /home/?/whodidit/parse_osc.pl -h <host> -d <database> -u <user> -p <password> \
    -l http://planet.openstreetmap.org/replication/hour/ \
    -s /home/?/whodidit/state.txt -w /usr/local/bin/wget

Now each hour your database will be updated with fresh data. Note that the same osmChange file should not be processed twice: the database has no means of skipping already processed files.

If you do not want to wait several days to import backlog of changesets, you can download a weekly backup (and a relevant state.txt) from http://zverik.osm.rambler.ru/whodidit/backup/

Make a directory inside www root, for example, /var/www/whodidit. Put all files from www directory in it. Then create another directory, /var/www/whodidit/scripts and put there all four PHP scripts from scripts.

Update the line <script>var scripts = 'http://localhost/wdi/scripts/';</script> in index.html with the absolute URL of the directory you've put PHP files in. Then edit db.inc.php script, updating $frontend_url variable with the absolute path to index.html.

Then write your database parameters into connect() function in db.inc.php, and you're set.

• parse_osc.pl: This script downloads and parses replication diffs, storing changeset information in a MySQL database. It can create tables (with -c switch). Run it without parameters to see a list of all possible options.
• db.inc.php: Global settings for PHP scripts, also two useful functions (which can be updated in later versions, so be careful not to lose your settings -- sorry).
• tiles.php: Queries the database for tiles in an area. Returns JSON with either error message (large areas and areas that have more than 1000 tiles are rejected) or all tiles with changeset numbers and other information.
• changeset.php: Returns a JSON with detailed information for requested changeset ids. When called with latest=1 parameter, returns the latest changeset.
• rss.php: As the title suggests, it generated an RSS feed with the latest changesets in a bbox.
• index.html: The HTML page is a front-end to WDI infrastructure. It makes use of all PHP scripts and allows user to check WDI tiles and aquire RSS links.
• whodidit.js: The JavaScript behind the front-end.

Everything here (except OpenLayers, of course) is written by Ilya Zverev, licensed WTFPL.