I highly doubt they are "branching out" from just HN. Obviously Algolia existed prior to replacing hnsearch (they were already in YC), but taking it over gives them more visibility within the startup community and also frees up responsibility for Octopart.
Yes, we already existed before operating the new HN search. We did it as a way to participate to the community and of course it's good for our visibility. The hnsearch.com domain is the property of Octopart, not ours.
Seems like it might be something where they want to branch out from just HN.