If you control a bunch of established accounts, you can use them to either shill for products, or upvote certain topics.

- Spam a product/service

- Generate age so spamming a product/service is easier and the account appears more trustworthy

- Influence discussions in a particular direction for monetary gain, i.e. "I got rich on bitcoin, you'd be crazy not to invest".

- Influence discussions in a particular direction for political gain, i.e. "I went to Xinjiang and the Uyghurs couldn't be happier!"