Because newsletter templates are available in all variety of lengths and sizes, there is really no limit to the content that you could potentially write. Keep in mind, however, that you should probably keep down your word count to a level that people are comfortable reading. While you may think everything that you are spouting off is fascinating, it's helpful to first sit down and make an outline of what you want your main message to be, or what the major news is that you are trying to share.
Of course, the reason why you would like your memories to be mounted to a scrapbook instead of a photo album, is because you would like it to be special as much as possible. When you create a scrapbook of your own, you do not have limitations in adding as much creativity as you want, unlike photo albums, you are entailed to use only the spaces that are allotted for pictures. And since photo albums are ready made, it's difficult to make a personal touch for your own preference.