> Most spam I receive [...] originates from Gmail
> Spam is only “solved” on big providers because they mostly accept mails only from other big providers.
I would say that only accepting emails form other big providers isn't a good solution then.
Of course I can't prove this and is just from my subjectiviy and limited experience, yet...
I've reasons to believe that Gmail users get more spam emails as they report these.
It would be nice if such outsourcing went into other parts of the net (e.g. captcha).
Spam is only “solved” on big providers because they mostly accept mails only from other big providers.
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I would argue that “running an independent mail server” and mass-mailing are two entirely separate concerns.