Given a big corpus of literature one of the fun things to do is look at how the use of a term has changed over time. When did people first use a particular word? When did one word start to replace another, etc.? Google's Ngram Viewer is perhaps the best known tool for exploring these questions.
In the context of biodiversity doing something similar for BHL is an obvious thing to do. I've made various clunky attempts in the past (e.g., Biodiversity Heritage Library sparklines) but these all died.
Ryan Schenk (who did a lot of the user interface for my BioNames project) wrote a very stylish tool to display changes in names over time. Called "Synynyms" his tool is now defunct, but you can read about it here and the source code is on github. Ryan would take a name, find synonyms, then graph the changes in use of all those names over time.
The death of Synynyms has not gone unnoticed:
@rdmpage Is there a service simiar to synynyms to check for nomen usage? synynyms is not available anymore :(— JCAM (@PhyloJCAM) December 12, 2016
I've had a tool for my own use that searches BHL for a name and displays the results after first trying to aggregate the hits in a sensible way. For example, if there is more than one hit in a scanned volume, and those hits al fall on pages in the same article in BioStor, then I display the BioStor article, instead of a list of each hit separately. Inspired by @PhyloJCAM's question I've built a simple tool to explore the use of one or more name over time.
Located in the "labs" section of BioStor, the BHL timeline takes one or more names and searches for those names in BHL, displaying the results as a chart and a list of hits. I often use it simply to search BHL for a particular name, but you can also use it to compare names, e.g. Aspidoscelis costata and Cnemidophorus costatus:
The timeline tool is pretty crude, and it's slow if there are lots of hits in BHL. So, it's not as slick as Synynyms (Ryan Schenk is a clever programmer than I am). Still, it is a useful way to explore BHL and discover articles that you might not have known existed.