Source Constraints

Source Constraints let you include or exclude traffic, and adjust how much you pay for it — whether the rule is set on a single campaign or on an entire exchange. In plain terms, this feature answers one question for every visitor: “Should this visitor see my ad — and if so, should I pay more or less for that click?”

The same tab supports two ways of matching traffic, chosen via the Constraint Type field:

• Source ID — target a specific traffic source.
• URL — target a specific website or page (sometimes referred to as “Block URL”).

Both match types share the same tab, the same rule fields, and the same Include/Exclude, Bid Modifier, and Budget behavior described below — the only thing that changes is what you’re matching against.

Where to Set Up a Rule

There are two places to create these rules, depending on how wide you want the rule to reach. Both screens work the same way and use the same fields (Include/Exclude, Exact Match, Bid Modifier, Daily/Monthly Budget) — the only real difference is how far the rule reaches: one campaign vs. an entire exchange.

Campaign Level

“Source Constraints” tab, inside a campaign.

• The rule affects only that one campaign.
• Use it when the rule is specific to one advertiser’s needs.
• You can set a Daily/Monthly Budget on the rule; once it’s reached, the rule pauses for that campaign.

Exchange Level

“Source Constraint” tab, inside Exchange Manager.

• The rule affects every campaign running on that exchange.
• You can apply it to all advertisers or to one advertiser only.
• You can also set a Daily/Monthly Budget here; once it’s reached, the rule pauses across every campaign on the exchange that it applies to.
• Use it for broad, publisher-wide decisions (e.g. “never show ads on this domain, for anyone”).

Caution

Budgets at the two levels don’t measure the same thing, so don’t expect a “$10” campaign budget and a “$100” exchange budget to behave the same way. A campaign budget tracks that campaign’s total spend. An exchange budget tracks only the spend that matched that specific rule, added up across every campaign on the exchange. Whichever one is reached first is the one that pauses.

Setting a Rule on a Campaign

Open the campaign, go to the Source Constraints tab.

Field	Description
Constraint Type	Choose Source ID to target a traffic source, or URL to target a website/page.
Domain / URL	Type the value to match — e.g. example.com or example.com/path. This field is labeled Source ID instead when Constraint Type is set to Source ID, and then takes a value like 4B2C7EBD.
Include / Exclude	Choose whether matching traffic should be allowed (Include) or blocked (Exclude).
Bid modifier	Optional % to raise or lower the price you pay when this rule matches.
Daily / Monthly Budget	Optional spending cap for this rule. Once it’s reached, the rule pauses for this campaign. Not available on Exclude rules.
Exact Match	Turn ON to match one exact page path; leave OFF to match the whole domain. See Exact Match.
Bid modifier only	Turn ON if this rule should only change the price and never block traffic. See Include, Exclude, and “Bid Modifier Only”.
Download / Upload	Export your current rules to a spreadsheet, or bulk-upload many rules at once.

Setting a Rule on an Exchange

Go to Account Info → Exchange Manager, open an exchange, then the Source Constraint tab (page titled “Global Source Constraint”).

Field	Description
Constraint Type	Choose Source ID to target a traffic source, or URL to target a website/page.
Source ID / URL	Type the value to match — e.g. a Source ID like 4B2C7EBD, or a domain like example.com.
Include / Exclude	Choose whether matching traffic should be allowed (Include) or blocked (Exclude) across the whole exchange.
Exchange	Shows which exchange this rule belongs to.
Advertiser	Choose All advertisers to affect every campaign on the exchange, or pick one advertiser to limit the rule to their campaigns only.
Bid Modifier	Optional % to raise or lower the price you pay when this rule matches.
Daily Budget / Monthly Budget	Optional spending cap for this rule, combined across every campaign on the exchange that it applies to. Once it’s reached, the rule pauses for all of them. Not available on Exclude rules.
Status	Turn a rule to false to pause it without deleting it.
Exact Match	Turn to true to match one exact page path; leave false to match the whole domain. See Exact Match.
Bid Modifier Only	Turn to true if this rule should only change the price and never block traffic. See Include, Exclude, and “Bid Modifier Only”.
Add	Saves the new rule to the list.

Exact Match — Whole Website or One Exact Page?

This switch applies when Constraint Type is set to URL — it decides how much of the URL needs to match. It works the same way on both screens.

You typed	Exact Match	Visitor comes from	Result
site.com	OFF	site.com/anything	Matches — the whole website is covered
site.com/psychology	OFF	site.com/business	Matches anyway — without Exact Match, only the domain counts; the page path is ignored
site.com/psychology	ON	site.com/psychology	Matches — same page
site.com/psychology	ON	site.com/business	Does not match — this is the whole point of Exact Match: target one page without touching the rest of the site

Note

https:// and www. never matter for matching, and a rule for site.com automatically covers pages on blog.site.com too.

Include, Exclude, and “Bid Modifier Only”

Every rule does one of three things. Pick the one that matches what you’re trying to achieve.

• Exclude — Blocks the matching traffic. It never changes price — a blocked visitor simply isn’t shown the ad.
• Include (Bid Modifier Only OFF) — Acts like a guest list: only the traffic that matches an Include rule gets shown the ad. Everything else is blocked.
• Include (Bid Modifier Only ON) — Only adjusts the price for matching traffic. On its own it never blocks anything — all other traffic keeps flowing normally.

Caution

Be careful with Include rules that have Bid Modifier Only OFF: they behave like a strict guest list. If you only add one or two Include rules this way at exchange level, everything else stops being served on that exchange. If all you want to do is adjust price without blocking anyone, turn Bid Modifier Only ON.

Caution

Budget is the one exception. If a Bid Modifier Only rule also has a Daily/Monthly Budget and that budget runs out, the rule does stop serving that traffic — it doesn’t just remove the price change. Both screens warn you about this when you set a budget on a Bid Modifier Only rule.

When a Campaign Rule and an Exchange Rule Disagree

You don’t need to memorize a chart for this — one sentence covers every case: “If anything excludes it, it doesn’t get shown.” It doesn’t matter which level (campaign or exchange) is the one excluding, or what the other level says.

1. Exclude always wins — If either level blocks the traffic, it stays blocked — even if the other level explicitly allowed it.
2. Prices don’t stack for the same thing — If both levels set a price change for the same kind of match (e.g. both by URL), only the exchange’s price change is used — they are not added together.
3. Different kinds of rules do add up — A URL price change and a Source ID price change can apply together, since they’re looking at different things.
4. An advertiser-specific rule only affects that advertiser — An exchange rule limited to one advertiser never changes what happens to everyone else on that exchange.

Quick Examples

Exchange rule	Campaign rule	What happens
Excludes the site	Includes the site	Not shown
Includes the site	Excludes the site	Not shown
Includes the site, −50% price	Includes the site, −30% price	Shown at −50% (only the exchange’s price change applies)
Has an Include rule for a different site, with Bid Modifier Only set to false	Includes this site	Not shown — with Bid Modifier Only set to false, that Include rule acts as a guest list for the whole exchange; anything not on the list is blocked, including this site

A Few Things Worth Knowing

• If a visitor’s information is missing or incomplete (for example, no page URL was captured), the rule simply doesn’t apply and the ad is shown as usual. A rule never blocks traffic “by accident” due to missing data.
• You can always export your rules to a spreadsheet (Download) and re-upload a batch of changes (Upload / Bulk Upload) instead of adding them one by one.
• Turning a rule’s Status off at exchange level pauses it without losing your setup — useful for testing.
• When in doubt about whether a rule should block traffic or just change its price, that’s exactly what the Bid Modifier Only switch is for.