As well as showing your complete PC specifications, installed software, and hardware configurations, a report includes personal data like your user name, computer name, external IP address, Windows Serial Number, and connected wireless networks, to name some.
Speccy shows no personal details that can be used against you.
When you Publish a Speccy snapshot, personal information - like the external IP address - is not included.
Extra privacy is achieved by deleting each published snapshot after 30 days, and that each published link has a random URL to enforce only the people you send the link to can see your snapshot.
Data shown in the report is inward facing, that is, just visible by you. Any outward facing data, like your external IP address, is either already publicly available as this is the address you have with your Internet Service Provider, or is removed when published.