Popular hashtags in digital marketing include:

1. #digitalmarketing
2. #socialmedia
3. #contentmarketing
4. #SEO
5. #PPC
6. #emailmarketing
7. #affiliatemarketing
8. #inboundmarketing
9. #growthhacking
10. #influencermarketing

It is important to note that hashtags vary depending on the platform and even subtopic of marketing, the above are general hashtags that should be relevant in most context, for more specific and niched topic, you might want to consider using more specific hashtags.