Visforms offers several effective parallel protection methods. Spamming via forms can be successfully prevented.
Overview
An overview of Visforms protection methods to prevent spamming via forms.
Visforms spam protection plugin
Visforms offers the use of online spambot databases via its own Visforms spam protection plugin.
Anti-Spam-Honeypot
Use the Anti-Spam-Honeypot.
Protection with Captcha
Visforms supports several alternative Captchas.
Additional protection options
Additional spam protection options such as simple custom validation.