Confused by all these buzzwords within performance (programmatic) advertising? See this chart which hopefully simplifies all the bits and bytes and gives you an overview of the ecosystem.
(click image to see full size) 
Publisher do have their inventory which is normally ad space. This could also be content space in theory. They offer this to advertiser through their interface which is the Sell Side or Supply Side Platform (SSP)
Advertiser are looking for inventory. Their request goes through their interface which is the Demand Side Platform (DSP).
An advertiser defines what kind of inventory he is looking for. There for he use the existing date (E-Mail DB, Analytics Data, CRM, etc.) which he combines in his Data Management Platform (DMP). This DMP is directly connected with the DSP.
If a publisher would work directly with advertisers he would need to place hundred of different publisher tags on his website. To simplify it there are different Ad-Networks or Ad-Exchanges (which combines different Ad-Networks) between both of them. They are doing the data exchange between both. In direction of the publisher (SSP) they are implementing the ad-tags, in direction of the advertiser (DSP) they are handling the offers in both directions and sync cookies.
Beside you may here RTA (Real-Time Advertising) and RTB (Real-Time Bidding). RTA is the entire process will RTB is just the price bidding part.
Now we can bring in 3rd party data, the media agencies and the view with different publisher websites, different advertisers and the options who owns the DMP (advertiser or media agency). Different advertiser can work together like for example Audi and VW, they can combine their DMP and / or DSP.
(click image to see full size)
But who are the DMP, DSP, SSP provider? Here you have a great overview and very well filter to find the right one for you.
Best Data Management Platform (DMP) Software
Best Demand Side Platform (DSP)
Best Supply Side Platform (SSP) Software
And here’s another great overview, focussing on the Display Advertising Ecosystem (2016) with all players (on the German market) from Improve Digital 1)https://www.bvdw.org/presseserver/programmaticadvertising/kompass_programmatic_advertising_2016_2017.pdf
(click image to see full size)
