Recently, after the announcement of the April Event, Apple has created a new hashflag on Twitter. Hashflags are just normal hashtags, but with a small image/icon after them. They are usually used for promoting or increasing hype among the target customers in a marketing campaign.
For the recently announced April 20 event, Apple has made a new hashflag live.
When Apple made their first hashflag last year, many Apple fans on Twitter were really excited to see this new approach—and they took it to the Trending page. Worthwhile publicity for the Apple event. Since then, Apple has been making hashflags and custom like buttons for every Apple event, you can check them (older hashflags) out here.