Reddit Ads for a SaaS trial: subreddit targeting or interest categories?

Say you run a project management SaaS with a free trial and want to test Reddit Ads. You can target people two ways: by subreddit or by interest category. Subreddit targeting sounds more precise, but the audiences are small, and r/productivity is full of people who will never pay for software. My hunch is to start with communities where people ask for tool recommendations, since those users are closer to buying, and run interest targeting as the broader comparison. What I'm not sure about is whether those communities have enough volume to learn from in a few weeks. That depends on your budget and on how tight your trial-start event is. Has anyone tested both with trial starts as the goal, not just clicks?

I don't buy that recommendation threads are closer to buying. Someone asking "what tool should I use" is often still researching, or already has a free tool and just wants a second opinion. Starting a trial is a very different action from asking the question. I haven't run Reddit campaigns myself, but on search platforms the stronger signal is someone typing a specific category term, not the topic of a thread. Before you split budget, estimate how many people in those subs would realistically start a trial in a month. If that number is small, a few weeks of comparison won't tell you much.

I don't think the search comparison holds. On Google, the keyword tells you what someone wants right now. A subreddit only tells you where someone spends time, and a person reading a thread about project tools could be nowhere near wanting a trial. So it's really attention versus intent, and Reddit gives you plenty of the first and much less of the second. That's why I'd measure something cheaper and closer to the trial, like pricing page views, instead of waiting on trial starts that may be too sparse to read in a few weeks.

Agreed on the attention versus intent split. Pricing page views get polluted fast on a SaaS site, though. Existing users check their plan, support staff click through, and some visitors are just comparing you against a competitor. Filter the event to logged-out visitors before you trust it, or the number will look healthier than your audience really is.

Also check how many trial starts you got last month before picking a proxy. If it's only a handful, the filtered pricing view is the better thing to test on.

I'm not sure the pricing page works as the proxy, even filtered to logged-out visitors. Someone who lands on pricing from a Reddit thread is often just checking whether you're expensive, and that same curiosity is what makes people skip a trial. So the event can look healthy while the trial rate stays flat.

If trial starts are too sparse to judge on, test a step that sits between the pricing view and the trial, like the signup form being started, and judge each subreddit against that. Your filter cuts the noise, but it doesn't close the intent gap.

Signup form is a better step than pricing, agreed, but the event definition decides whether it's useful. A "form started" event that fires on any field focus will count people who tab through by accident, autofill, or just peek, so you're measuring curiosity again. I'd fire it on the first real submit attempt, or on completion of step one if the form has steps. That's a smaller number, but it's closer to someone who meant to sign up.

Attribution is the bigger risk. If the form lives on an app subdomain and your Reddit pixel sits on the marketing site, the event may never carry the click back to the subreddit. Then every community looks like it produced nothing, and the comparison is just noise. Make sure the pixel and the event share a domain, or that cross-domain tracking is actually working, before you compare any numbers.

Agreed on attribution. Before anyone splits budget, I'd work backwards from the number of events you need. Say you want roughly 30 trial starts per community before you compare them, and your Reddit click-to-trial rate is around 2%. That works out to about 1,500 clicks per subreddit. If a sub can't realistically deliver that in your window, don't rank it on trial cost. Rank it on a cheaper step instead, like a completed form step one, and treat whatever you see as a hypothesis to test later.

The 2% is doing most of the work in that math, and cold Reddit clicks usually convert worse than warm search traffic, so 1,500 per sub could be optimistic. I'd anchor the estimate on whatever your existing paid traffic converts at. What does that rate look like right now?

Yeah, 2% is optimistic for cold Reddit clicks. The other thing nobody's brought up is that trial starts per sub are capped by how many people in that sub actually match your geography and language. So check the reachable audience size in Reddit Ads before you lock in a 1,500 click target, because a small sub can't deliver that no matter how good the creative is.