You can bypass the the "Please enter a valid message." restriction pretty easily. All you have to do is use empty bbcode tags (Bold seems to reproduce it fairly easily). See the below post for an example. Sorry if this isn't considered a bug. Kyle.
There are a few other ways you can do similar things - 1x1 image, text the same as the background, etc. It's not possible to prevent, so it's more something that needs to be handled by active moderation.
Well, posting with a 1x1 image still contains content, along with 'invisible' text. This is a content less post, which is possible to prevent. While I don't think this is resolved at all, alright.
Completely different beast @DBA, same with @Mike's examples. You shouldn't be able to bypass the no content post restriction by using bbcode. Posting an image, or posting with the same bg contrast/colour font is completely different. Why is it different? There is actually content! This is clearly a bug, there's nothing I can do besides making my own edits if the authors think otherwise. Appologies for grammar/spelling, I'm on my phone.
