Topic renamed to give others a chance to know what it's about before clicking here.
Why would you want to post in your own messenger?
The reason it is considered spam, is because a bunch of people post completely random things just because they are bored or have figured out that they can earn AP that way. It is not outright forbidden, only strongly discouraged. I occasionally post on my own profile to make a little note so I know what messages I have replied to and such. I usually delete them afterward...
If you have a short message to people who stop by your profile, add it at the bottom of your About. If you have a map you want to save, do so in Notepad or a similar text program.
Any other reasons you'd want to post in your own box?
Oh, I just realized. You have been using your profile comments as if they were posts in a thread... Yeah, that is discouraged because a lot of people don't check back on people they have messaged, and therefore you should write the replies to them on their profile, not your own.
Imagine having a conversation with 25 different people. Would you remember to check back on everyone, or reply to all the messages? I certainly wouldn't...
So uhm, yeah. Just talk by posting on their profile and let them respond on yours. That's how the system work best, though we could definitely use some sort of 'reply to' feature...