Short answer: pick posts about your topic, collect the people who commented or liked them, keep those who fit your target, then write to them about the post's subject. Sales Farmer, a LinkedIn and email prospecting tool, collects and sorts them, and nothing is sent until you click Launch. A comment is worth more than a plain like.
Updated November 2, 2026.
Why prospect from a post?
Someone who reacts to a post has raised a hand on a subject, today. That is a stronger reason to write than a job title in a bought list, because you can talk about what is on their mind.
The limit is plain: a reaction is not buying intent. Some people comment out of politeness, others to disagree. Expect uneven replies and test on a small group before you scale. For more on signals, read our article on LinkedIn buying signals.
Which posts should you pick?
A good post gathers people who look like your customers. Three kinds work well.
Your own posts come first, since the people who react already know your name. Next come posts by people who speak to your target: experts in your field, leaders of neighbouring companies, content creators. Last, your competitors' posts, where people who care about your topic gather before they have met you.
Skip viral posts unrelated to your offer. A thousand passing comments do not make a thousand prospects, they fill your list with the curious.
Which sources does Sales Farmer read?
Sales Farmer reads four sources, through the Chrome extension and from your own browser.
- Your posts: those of the last 14 days (six at most), with reactions and comments.
- Watched profiles: their posts of the last seven days (five at most), with the people who commented. The Starter plan follows ten.
- Topics: you give three to eight topics, the extension searches recent posts on them every day (five new ones at most per reading) and collects reactions and comments.
- Competitor pages: up to thirty new posts per reading, over a 90 day window.
Reading competitors and topics belongs to the Growth plan and the free trial. Each source is read once a day, and all LinkedIn reads are capped at 150 per day. Past that, nothing is read until the next day.
How are people collected and sorted?
First you describe your business: your target, and what you want to leave out. Without that description, sorting is pointless.
Sales Farmer then keeps everyone who reacted and ranks them on the "Validate people" screen. Each person shows a source, such as "commented on a post by", a Matches or To check label, and a warmth level with its evidence. People the tool sets aside stay visible with the reason, and you can put them back.
A competitor's own team is set aside automatically: its employees are not your prospects.
How do you read the strength of a signal?
Not all reactions weigh the same. A comment tells you what the person thinks, in their own words. A like only tells you the post passed in front of them. On watched profiles, Sales Farmer therefore reads the commenters, because under someone else's post a reaction alone is a weak sign.
Under a topic or a competitor page it reads both, and the warmth level counts a like for less than a comment. Several reactions from the same person in a week raise it. Start with the warmest people and leave the rest for a second pass.
How do you contact them?
You validate the list, read the sequence, then click Launch. The invitation goes out without a note, and the first message goes out once the invitation is accepted. You can edit it person by person.
Talk about the subject of the post, not about watching reactions. "I saw you commented on the e-invoicing post" sounds like surveillance. "Your comment on e-invoicing made me think of a question" opens a conversation. Templates are in what to write to someone who commented or liked a post.
What pace should you keep?
Stay at human volumes. Default caps are 20 invitations a day and 100 a week, but LinkedIn bans tools that automate its site, and no setting makes an account immune. Details are in the article on automation limits.
Keep reading
- Watch your competitors on LinkedIn to find prospects
- Social selling with the Sales Farmer extension
- Sales Farmer pricing
FAQ
Should you write to people who only liked a post?
Rarely on that alone. A like is a weak signal: it justifies a message when it adds to something else, such as a comment, a matching job title or several reactions in the same week.
Can you prospect people who reacted to a competitor's post?
Yes, these people are not tied to anyone. Sales Farmer reads competitor pages on the Growth plan. For personal data rules, read the article on GDPR, then have a lawyer check your practice.
Do you need to give your LinkedIn password?
No. The extension works in your browser, with your session, and Sales Farmer never asks for your LinkedIn credentials.
How many people does a source bring in per day?
It depends on the posts. On a topic, the tool keeps 25 people at most per post and 120 per day. A short, well targeted list beats a long lukewarm one.
Does anything go out without my approval?
You validate each person, and nothing is sent before you click Launch. You can pause a campaign at any time.
Try it on your own topics
Pick three posts in your field and look at who reacts. Try it free for 14 days, no credit card needed.