How to cancel hard disk from wanting to format and how to get my files back?
This question is tagged data but you know it's about data from hard-drive-recovery.

Best Light Software to Manage Large Amounts of Data?
This question is tagged both database and data, but database inherits data, right?

How to quicky connect to a sqlite database with OpenOffice.org Base?
This question is tagged data, but shouldn't it be tagged database instead?

data Shows some more issues of tags that are actually multiple words and might need a hyphen:

• Should [free] + [data] be [free-data] or just [free]?
• Should [data] + [query] be [data-query] or just [query]?
• Should [data] + [validation] be [data-validation] or just [validation]?
• Should [data] + [file] be [file-data] or [data-file] or [file] or maybe nothing or something else?
• ...