I think I might be inclined to use IncludeText fields to reproduce bookmarked portions of a document that contains the updated texts.
{ INCLUDETEXT "C:\\Path\\Blurbs.docx" "Bookmarkname" }
This document can easily be updated as required, just making sure that you don't delete the bookmarks it contains.
The only problem with this method is that the fields do not update automatically, so you would have force an update when the document was opened. You can use the macro code example at
http://www.gmayor.com/installing_macro.htm to do that.
Inserting the fields in many hundreds of documents (or updating them) will be a trial, but
http://www.gmayor.com/document_batch_processes.htm should help with that. It wouldn't be difficult to create a custom process to open the documents, unlock then update the fields, then lock them again, and it could be run over a lunch break which would avoid leaving users responsible for the updates.
An alternative is to paste links to selected texts in another document. While such links will update readily, the blurbs document may be more difficult to manage.
You may also find
http://gregmaxey.com/word_tip_pages/repeating_data.html useful.