Brenda automatically deletes messages that does not qualify as a valid alert information. To be considered valid, the message must include at least an Amazon VINE product URL and/or a category/user mention.
Additionally, to cut down on clutter- she will only allow an item to be posted once. So if you try to share an item at the same time as someone else, only the first share will be posted in the alerts channel.
Posting the right link is extremely important to the way that Brenda functions, so please also check out: How do I find the right link to share?