Could you provide some sources here?
> They've probably created a very large Freebase graph for scale testing and it's likely that they're able to handle 500M entities from a hardware perspective.
If this were reality it would be a pretty big lie on Google's part. Why do you think this is the case?
EDIT: OK, now I realize why your comments trigger my BS alarm. It's in your interest to represent the Google knowledge-graph as being equivalent to Freebase/metaweb (a Google acquisition many years ago. Do you really think they did nothing to increase their graph since that acquisition?) because you are the founder of Ontology2 (the company providing this service). You really should mention that somewhere in this thread or on your profile (I realize your comments elsewhere in this thread allude to it -- for the claims you are making without sources that's not enough IMHO).
The rate at which we add entities to the Knowledge Graph is different from the rate at which those entities appear in search. What you see in search now is just part of the Knowledge Graph but we're continuously increasing the coverage while making sure that the quality of the data remains extremely high. I guess that's what you would call the "visible GKG"; to us, its all one big graph.
We do know that they ported "graphd", the Freebase database, to Google's infrastructure. Really nothing happened at Freebase for a year and a half while they were doing this.
They've probably created a very large Freebase graph for scale testing and it's likely that they're able to handle 500M entities from a hardware perspective.
If you look at how often the GKG comes up in search, it clearly doesn't come up very often. So the process that makes the visible GKG is a process of subtraction, not addition. There are many topics where the GKG could give you an answer from Freebase but it doesn't, and they prune many of them away because they don't want to take the chance of giving wild answers. It's more likely that 1 or 1.5 million topics are in the visible GKG.