Depends on how you define normal for the modern Internet.
Dynamic IP addresses and botnets are common, so I would suspect that your IP address (at the time of signing up) was previously identified as a source of spam, hence the verification.
In short, don't take it personally. Spam is mainly automated, and thus we must play that "cat and mouse" game by utilizing automated anti-spam solutions, lest we drown in the sewers of the Internet... not to be confused with Facebook.
