Hashtag
Social MediaAlso: Pound Sign Keyword · Social Tag
Quick definition
A word or phrase prefixed with the # symbol that categorises social media content and makes it discoverable to users searching or following that topic.
Where it shows up in the data
Hashtags are filing tags. When a user clicks or searches a hashtag, they see all content tagged with it. They extend your content beyond your followers to anyone interested in that topic.
Company-specific hashtags like #NikeJustDoIt or #ShareACoke serve a different purpose from topical hashtags: they aggregate brand content and encourage user-generated content (UGC) under one searchable term.
Popular hashtags (#marketing, #business) have millions of posts and extremely competitive feeds — your content disappears within seconds. Niche hashtags (#melbourneaccountant, #ecommerceau) have less volume but your content stays visible longer and reaches a more targeted audience.
Hashtags work differently across platforms. On LinkedIn they function more like topics for professionals. On TikTok the algorithm uses them as signals but keyword search is increasingly more important. On X (Twitter) they are still core to conversation threads.
What it actually means
Hashtags are metadata tags that make social media content searchable and categorisable. When you include #digitalmarketing in a LinkedIn post, that post appears in the feed of anyone who follows or searches that hashtag. The strategy behind hashtag selection matters: too broad and your content is invisible in a stream of millions. Too narrow and no one is looking. The sweet spot is specific enough to attract an interested audience, broad enough that people actually search it.
A hashtag on a crowded tag is a whisper in a stadium. A hashtag on a niche tag is a shout in a room.
How it shows up
Instagram Insights shows reach from hashtags per post under 'Impressions'. LinkedIn Analytics shows 'Discovery' reach which includes hashtag-driven impressions. Use these to compare hashtag performance across posts and identify which tags are driving genuine reach versus being ignored.
The Australian context
Australian-specific hashtags like #aussiebusiness, #madeaustralia, #australiansmallbusiness and location-specific tags (#sydneycafe, #melbournefitness) are useful for reaching local audiences. LinkedIn's Australian professional community is active and topical hashtag following is higher than global averages per capita.
Where people get this wrong
Related terms
Common questions
How many hashtags should I use on Instagram?
Instagram recommends 3-5 relevant hashtags in 2023 guidance. Research supports this over the old advice of using all 30. Focus on specificity and relevance over volume.
Do hashtags work on LinkedIn?
Yes. LinkedIn hashtags function as topic categories followed by professionals. Using 3-5 relevant professional hashtags on posts increases reach to non-followers. Add hashtags in the post body or comments, not buried at the end of a long caption.
Should I put hashtags in the caption or comments?
On Instagram, both work. Putting hashtags in the first comment keeps the caption cleaner. On LinkedIn, hashtags in the post body work better. On TikTok, hashtags in the caption are standard and also serve as signals to the recommendation algorithm.
Keep exploring
About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
How we think →