Many new users complain here about the (admittedly awful) Captchas, and the (reasonable) reply from most regular users is Spam protection".
I logged on today and there are 6 pages of such spam. Clearly the “spam protection” is no such thing.
I volunteer on many support forums of different types/disciplines and Avast’s (a cyber security company) has the worst record of any by a long, long way 
C’mon guys :-[
We Avast users (with permissions), who have been deal with this cr4p for a very long time are constantly asking for anti-spam measures. Even those of us trying to deal with it are in many different time zones but we can’t be on-line 24/7.
I’ve been following such complaints/Requests by the folks (with Permissions)trying to deal with Spam increase for a number or years, the ones addressing the spam I know are doing all they can and still no anti Spam measures to assist. :-\
Yes coinbase spam again and again. Just keep reporting to moderators. Guess they have limited capacity to stop it as it keeps coming back again and again. Seeing it here all the time, does not do Avast reputation any good IMO.