It is actually 1. Advertise open positions that aren't really open 2. Get a feel of the market and see how many candidates you get and what salary they ask 3

It is actually 1. Advertise open positions that aren't really open 2. Get a feel of the market and see how many candidates you get and what salary they ask 3. Gain brand awareness because candidates are used to your name 4. Test the effectiveness of your hiring/advertising channels without actually hiring anybody 5. When you actually need to hire somebody you already know what salary people ask, you know what kind of people will find your ad and you focus only on current CVs