Searching for tags, using the inname parameter AND a date range returns only the tags that were created in that period, not the tags that were used in that period. When searching by inname only, or date range only the API returns all tags used (matching the criteria).
See this example: https://api.stackexchange.com/2.0/tags?fromdate=1322697600&todate=1325116800&order=desc&sort=activity&inname=java&site=stackoverflow