When to rebuild and when to reorganize indexes

I have been trying to gather information about rebuilding and reorganizing indexes. From stackoverflow page (How Often should the indexes be re-build in sql-server DB?) i got this query : SELECT t.NAME 'Table name', i.NAME 'Index name', ips.index_type_desc, ips.alloc_unit_type_desc, ips.index_depth, ips.index_level, ips.avg_fragmentation_in_percent, ips.fragment_count, ips.avg_fragment_size_in_pages, ips.page_count, ips.avg_page_space_used_in_percent, ips.record_count, ips.ghost_record_count, ips.Version_ghost_record_count, ips.min_record_size_in_bytes, ips.max_record_size_in_bytes, ips.avg_record_size_in_bytes, ips.forwarded_record_count FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'DETAILED') ips INNER JOIN sys.tables t ON ips.OBJECT_ID = t.Object_ID INNER JOIN sys.indexes i ON ips.index_id = i.index_id AND ips.OBJECT_ID = i.object_id WHERE AVG_FRAGMENTATION_IN_PERCENT > 0.0 ORDER BY AVG_FRAGMENTATION_IN_PERCENT, fragment_count The problem is that when i rebuilt indexes the avg_fragmentation_in_percent increased instead of decreasing. Any pointers?? If this is the normal behavior then what am i missing here?? Previously the avg_fragmentation_in_percent was 30 and after rebuild it has increased to 66.