PSA: 'Suspicious comments' and 'Spam comments'-- LJ decision to 'block' spam
Long story short:
LJ has created a new filter that is AUTOMATICALLY TURNED ON in ALL journals and communities, which screens comments that are made with 'suspicious links' ie links that are not on their safe whitelist, so pretty much the majority of the internet.
To turn it off: Go to yourSettings, click on the Privacy tab, and half way down where it says Spam Protection uncheck the box next to "Comments containing a link to a non-whitelisted domain will be marked as spam and moved to a special section." This applies to both personal journal and communities and the opinion has to be manually changed in each one.