Forgive my lack of technical knowledge but.... when you open whatsapp, at the bottom of the page are five icons, the first of which is labelled Status. Lately I’ve started seeing generic kind of greetings on there from the same person, and there is the option to reply. Would these be greetings sent to everyone in their WhatsApp address book, or just for me? If the latter, why use Status and not just send a message ?
The list that you can see in the tab labelled "status", is where people have updated their WhatsApp status. You can click on a status and reply to it if you want.
You can update your own status and anyone that has your number in their phone, will see your status in pretty much the same way that you can see other status updates.