Nalin: Er, the post implies that the MD5 posts aren't needed anymore for new versions of the installer. The installer itself will verify the MD5 of the archive when you run it. Why bother with recording the MD5s then?
Posting the md5 hash is still a good paradigm to follow even if the installer has the ability to do so on it's contents. Not only is it open source easy to automate software, but also greatly aids in troubleshooting (especially for the bandwidth challenged customers). Quite honestly if someone were having install problems the 1st logical step in troubleshooting would be to verify the hash. This would easily identify an improper bit order that could possibly affect the installer's ability to properly report to the user the difference in hash.
Plus you can easily check if your build of a game is current with GOG, especially in these early stages where the kinks are being worked out and new builds are frequent.
Saves time troubleshooting if needed - saves money on bandwidth. Posting the current md5 hashes I feel is still very relevant.