à propos the subject line rather than the content, I have just had some really good results from writing direct to the librarians/archivists at local newspapers with specific requests. For example, I was recently trying to find an obituary rumoured to have been in the Cork Examiner for a date in September 1855 for one Edward Henry A'Court. Finding the Cork Examiner had been subsumed under the banner of the Irish Examiner, I wrote to the latter. Within a few days I received a very full reply, with a copy of the microfilm record of the entire paper for that date, together with advice as to where I might find further information. As it happens, there is no such obituary for the date in question, so there is more wok to do. My point is, however, that this is the fourth or fifth time I have had assistance from local newspapers in the UK and France - a very good resource for serious research, provided, I suspect, it is not abused.
I also find the online search facilities for the London Gazette to be extremely useful. I haven't yet found whether there is a similar facility for the Moniteur - that is a path yet to be trodden!