There are a number of things you can trademark to protect your business in the online world:
- Website domain names
- Brand/product names
- Sounds (ex. Law and Order’s “chung chung”)
- Hashtags (ex. #sayitwithpepsi)
You are only able to trademark something unique (i.e. you can’t trademark “clothing” for a clothing company) and related to how you promote and advertise your brand.