Although I couldn't find anyone else looking for the same people I was looking for (largely because they have only pseudonyms in my grandfather's diaries -- in one case because he didn't know the woman's real name, and in the other case to protect the man's descendants from embarrassment -- though I hope that with the passage of more that 100 years, any such embarrassment would be irrelevant).
But I did find one person looking for someone else I sought. I wasn't sure if it was his real name in the diary, but it looks like it not only might have been the correct name but I might just have found his grandson.
Those of you who read The Accidental Anarchist will remember Glasnik, a friend of Jacob Marateck's from Vishigrod with whom he was conscripted in 1902. I found one person searching for Glasnik, and it took several months to find a current email address, but I did finally hear back from Glasnik's grandson, now a real estate professional in Israel. He didn't know much about his grandfather (though he gave me his full name) and was going to look for information. In the meantime, I sent him the first half of my book, those chapters in which Glasnik appears, and I look forward to receiving confirmation that I have found the real Glasnik's real grandson, and learning what happened to him after the end of the Russo-Japanese War. I will share that information here when I hear back.
In the meantime, I continued, when I was bored or wasn't able to focus my mind on the work I needed to do, looking for descendants of other individuals in the book. Much to my frustration, I feel it's unlikely that I'll ever be able to identify the real Pyavka, notably since his nickname, "The King of Thieves," is not likely to be the term through which any descendant might seek information about him, but you never know. I'll go back to Jewish Gen and maybe post the question myself.
I am also trying to identify the real Divanovsky, department store magnate in Irkutsk, but have had no luck googling variations of "Jewish," "department store," "rich or wealthy," "business," "Irkutsk," though I will keep trying.
But last night my search turned up something completely different but also intriguing, and will shortly post the article that is sending me in a new direction.