I am sorry to hear you are experiencing this issue. Can you confirm for me if you are using a Constant Contact sign-up form or a third-party sign-up form?
It's genuinely mind-boggling that Constant Contact doesn't have a authentication catpcha option available for its sign-up forms. Now I have to go pay a developer $2,500 to build a customized one, so I don't have to spend 10 hours each month sifting through email signups and guessing which ones are spam, and then another 10 hours identifying spam clicks on content contained in our newsletters. Ugh.
I just deleted another 63 bot sign-up name/emails. This is an ongoing problem. My understanding is that unless more than 50 sign up in a 24 hour period, you are unable or unwilling to activate a filter/prevention system. Unless this situation changes I'll be relocating my business to a service that features stronger protection against this time-wasting issue.
I'm so sorry to hear that! I can assure you that we have parameters in place that look at activity patterns regardless of time limits or reaching a "trigger" amount. Contacts that we suspect as being suspicious are immediately marked as Temporary Hold and are not added to a list nor your active total count. You can review contacts that show as Temporary Hold before adding them to a list. This type of activity affects all email service providers so we are happy to address any questions you have in this area. Please see guide for more details: Contacts Marked as Temporary Hold. We also have a dedicated Account Review team that can also answer questions you may have. If you'd like to speak to them, please see how to reach them here: Contact an Account Review and Deliverability Specialist.
I hope this helps! Please let us know if there is any other way we can assist.
There currently is not a way to implement CAPTCHA for every sign up, however the Constant Contact sign up forms will automatically add a CAPTCHA after 50 sign-ups in one day. You can also turn on the Confirmed Opt In feature in the account for a double opt in process that will keep the spammers from getting on to your lists. Here is an FAQ that goes over how best to keep out spam emails using Constant Contact. Thank you for reaching out to the Community for your query!