John Goldin got in touch as he’s put together a page that quickly searches the diary and shows charts of the frequency of words throughout the text.
The search results (or the chart, if you’re viewing the Histogram tab) will update as you type, or you can keep clicking the Examples button if you can’t think what to search for!
You might find it more (or at least differently) useful to this site’s own Google-based search, especially as the searching is more precise and potentially detailed (see the Help tab).
One thing I’d point out — to search for a whole word, surround the word with \b (a backslash followed by a “b”). e.g., to look for the word “war”, search for \bwar\b. The \b indicates a “word boundary”, like a space or punctuation mark. Without those you’ll also match “Edward”, “towards”, etc.
If you find any particularly interesting things, post in the comments below. I like the Histogram for “plague”. Many thanks for this John!