I need to know for a project centered around achievements, furthermore the date they were unlocked. I want to mitigate the fact that some achievements before a certain date had no timestamps for statistical reasons.
The earliest indication of an exact date that achievements were assigned timestamps I could find is 2008-10-25 but I could not find any official statements so far. Is there an earlier known and/or even official date?
In addition, what's the exact date that Steam achievement became available in general (without timestamps that is)?