The questions that come up before anybody pays.

These are written for three people, and each of them asks about something different. The salesperson wants to know how many leads this really produces and how long they take to work through. The owner asks what it costs and whether the tool stops working in a month, the next time Facebook changes something. The person responsible for data protection has to sign off on what happens to other people's data, and needs a sentence they can repeat in a meeting.

The order matters only at the start. Begin with the piece on whether this is legal — it is the first question asked, and until it has an answer the rest of the conversation stops. Then read how much is actually visible without logging in, because that is what sets the limit on what any tool of this kind can promise. Read the rest when you need it: when somebody proposes writing a scraper in-house, when the scan time has to be set, or when leads should land in Zapier rather than in an inbox.

The numbers in these pages are ours — measured on live IP addresses and on frozen copies of Facebook's own pages, not taken from somebody else's round-up. Every guide carries the date it was last checked, because Facebook changes without notice and a measurement from six months ago is no longer a measurement. Where we have not measured something, we say so.