Selecting web element for data and looking for update would be fairly easy. PDFs which contain tabular data could be converted to CSV and then particular cell could be selected.
It is the non tabular PDF data which could be bit tricky to select data from and might require some image processing work to be done.
Overall, I think this is an interesting problem and given enough need gap it would be worthwhile to solve this; as those who consume the data you have pointed out regularly might feel there is a need.