I think I found a way for collecting and storing testimonials: Excel.
A while ago I started a trello baord but while finding key words there is easy via the search function I have to do a lot of clicking to get inspiration. I like to react to what I read with an idea for an email or a blog or whatever.
Then I realized I started an Excel spreadsheet a while ago. It has some 45 entries already but I have a ton more that I need to enter. It's much easier for me to handle as I by glancing over them, scrolling through the file I get inspiration and that makes the collection more valuable.
With regard to pieces of copy I think I will open a Word doc / Google doc.
Any experiences with it?