The story. Taboola launched Realize ID on 22 September, and 51Degrees followed with its own identifier, 51Did, the same week — two new entrants into a post-cookie identity market that already runs LiveRamp’s RampID, The Trade Desk’s Unified ID 2.0, ID5, Yahoo ConnectID, TransUnion’s TruAudience and PayPal Ads ID. AdExchanger’s framing of the problem: advertisers want “a ubiquitous coin-of-the-realm-type ID,” and what they have instead is “credits at a Dave & Buster’s-esque chain with its own currency that you can only spend on site.” (AdExchanger, “More Alt IDs, More Problems,” Daily News Roundup, 23 September 2026)
01What happened
- Taboola’s Realize ID launched 22 September, pitched by CEO Adam Singolda as a tool “helping performance marketers capture and act on open web intent before it disappears” — an identity product built to preserve targetability as third-party signals decay.
- 51Degrees released 51Did the same week, a data services company affiliated with the Movement for an Open Web entering a field AdExchanger describes as already crowded.
- That brings the named field to at least eight alternative IDs, none of which interoperate with each other by default: RampID, UID2.0, ID5, ConnectID, TruAudience, PayPal Ads ID, and now Realize ID and 51Did.
- AdExchanger’s own read is that this is fragmentation, not competition solving the problem. Each ID works inside its own walled ecosystem, closer to store credit than a shared currency, which means a publisher plugging in a new ID gains reach with that ID’s specific demand partners, not with the market broadly.
02What it means inside a GAM network
Every new alt-ID launch is pitched as solving identity resolution; what it actually solves is identity resolution for the demand that has already integrated with that specific ID. For a publisher running PPID and first-party data strategies inside GAM, the operational question was never “which ID is best” — it’s how many of these a stack can reasonably carry before integration and QA overhead outweighs the incremental demand each one unlocks. Realize ID’s pitch is squarely Taboola’s own demand-side reach; 51Did’s is whatever the Movement for an Open Web’s affiliated buyers bring. Neither is a market-wide fix, and stacking IDs without a floor-and-fill strategy behind each one is how a publisher ends up running eight parallel identity graphs for marginal gains on most of them. The operator question this desk keeps returning to on alt-ID stories: does adding this ID measurably lift matched-bid rate and win rate against your own first-party segments, or does it just add another vendor tag firing on every page.
03What publishers should do about it
04The bottom line
This desk has covered the identity-fragmentation story from the yield-leak side and the agent side before; what’s new this week is concrete — two named launches, Realize ID and 51Did, in the same seven-day window, pushing the count of non-interoperable alt-IDs past eight. AdExchanger’s “credits at Dave & Buster’s” line is the accurate one: more currencies, still no common one, and the operator answer stays the same — build the first-party graph you control, and audit each alt-ID by the demand it actually resolves before adding the next.