You will receive a long list of benefits by being a SiteLock subscriber, both short and long term. Summarizing:
Protects your site: SiteLock will scan your website periodically to look for vulnerabilities and malware, protecting it against threats and ensuring it is not being blocked. Premium and Enterprise level plans include a full scan of your site, every day.
Increases your sales: Displaying the SiteLock seal on your website indicates that you are a trustworthy business, this increases trust, traffic, sales and conversions.
Speeds recovery: If your site is breached or corrupted, SiteLock will identify the problem and help you find a quick solution. You'll be up and running again in no time.
