I've created a post today: Alternative PCB Manufacturer to JLCPCB ? - General Electronics - Arduino Forum
The thread contains the names of several PCB manufacturers. The name of one PCB manufacturer, namely allpcb.com (A-L-L-P-C-B.com for non-logged in users) is completely filtered out if the user is using the Arduino forum without signing in.
This may have an impact on their business since it could influence search results.
Of course, there are obvious cases of spam from users, usually with a small number of posts, who advertise links to certain suppliers. If that is the case here, the individual posts should be dealt with but generally blocking the name of a business is. IMHO, a serious step.
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