Plumbline
How Example Topsite decides the order of the list.
A plumbline is the oldest tool for finding true vertical. You cannot argue with one, because gravity does the work. That is the claim this ranking makes: the order of this list is not a matter of opinion, and it is not a matter of who scripted the hardest.
Six stages, applied in order. Two run as each visitor arrives; four run every 5 minutes over the totals. Every stage is listed below with the settings this site actually uses, and every listing publishes its own score receipt showing the arithmetic.
| Action | Weight | Meaning |
|---|---|---|
| A visitor received | 0.2 | someone arriving from a listing’s own site |
| A visitor sent onward | 1 | someone clicking through to the listing |
| A vote | 3 | a deliberate endorsement, one per identity per cooldown |
1 Provenance as it happens
Every click and every vote is identified before it is worth anything. An anonymous visitor is pinned by network address and by cookie together, so clearing cookies buys nothing and neither does reconnecting on a new address. One identity counts once per listing per window. Automated clients score zero but are still recorded, because a listing owner is entitled to see what was turned away. Traffic that did not come from one of our own pages is halved rather than discarded, real browsers do suppress referrers, and throwing those visitors away would quietly penalise the privacy-conscious.
| Click window | 60 min |
| Vote cooldown | 24 h |
| Unknown referrer worth | 50% |
2 Saturation as it happens
The second visitor from a network counts less than the first, the tenth less again. Credit follows a square-root curve rather than a straight line, so two hundred addresses inside one hosting provider’s range are worth about fourteen genuine visitors, not two hundred. This is the stage that makes a rented botnet uneconomic: the cost of the attack rises linearly while the benefit rises as a square root, and the two curves never cross.
| Curve | sqrt |
| Grouped by | IPv4 /24, IPv6 /48 |
| Window | 24 h |
3 Gravity every recalculation
A score is not a running total, it is a position held against a constant pull downward. Activity loses half its value every half-life, without exception and without a monthly reset to game around. A listing that was busy last year and quiet since has already fallen; a listing that was busy this week is rising. The practical effect is that rank reflects the state of a community now, which is the only question a visitor is actually asking.
| Half-life | 7 days |
| Recalculated | every 5 min |
4 Cadence every recalculation
Two listings can arrive at the same total by very different routes: one drew visitors every day for a fortnight, the other bought a weekend. Cadence measures the share of days with genuine activity and scales the score by it, so the steady community wins. This is deliberately the stage that promotion cannot buy, a burst raises the total and lowers the ratio at the same time, and the two largely cancel.
| Window | 14 days |
| Weakest multiplier | 60% |
| Stage active | yes |
5 Ballast every recalculation
Three enthusiastic votes should not outrank three hundred. New and thinly attended listings are held down in proportion to how little is known about them, and the effect fades as real evidence accumulates. Without this stage a list reshuffles violently every time a new entry gets a handful of clicks, which is the single most common reason a ranked list stops being believed.
| Prior weight | 10 identities |
| Half strength at | 10 identities |
6 Plumb check every recalculation
Visitors who arrive at a listing and never click through to it are either manufactured or pointed at something that is no longer running. Either way the listing is flagged for a moderator. It is never silently penalised: an automatic deduction here would be a weapon, because anyone could aim fake traffic at a rival and watch their rank fall. A person decides, and the decision is written to the audit log.
| Click-through floor | 5% |
| Minimum evidence | 200 visits |
| Window | 14 days |
| New-listing grace | 7 days |
What this does not stop
Someone with a large pool of residential addresses, realistic browsers and human-looking timing can still push a listing up. No scoring method stops that. What happens instead is that the shape of the traffic stops making sense, visitors who never click through, activity that appears and vanishes, and the sixth stage refers it to a moderator. We would rather tell you that plainly than claim a guarantee we cannot keep.