What it usually means in practice
Most often: search and social, plus a website, plus reporting. That is three or four capabilities described with a phrase that implies all of them.
It is not dishonest exactly. It is that "full" is measured against what the provider offers rather than against what your market requires.
The list to hold it against
Demand capture: paid search, local service ads, and the profile and reviews work that feeds them. Demand creation: paid social, connected TV, streaming audio, digital out-of-home. Retention: retargeting and customer-list activation. And the plumbing: tracking, reporting, and creative production for all of it.
A provider covering the first group and calling it full service is covering a third of the surface.
Why the gaps matter more than they sound
Missing channels are not just absent options — they cap your growth. When you have captured all the search demand in your county, the only way up is demand creation. A provider without those channels will tell you the market is saturated, because from where they stand it is.
That conversation happens constantly and it is almost always a capability limit described as a market limit.
How to ask
Do not ask whether they are full service. Ask which channels they run in-house, which they subcontract, and which they do not run at all — then ask what they would do when search maxes out.
The answer to the last question tells you whether you have bought a plan or a ceiling.