I run out of space all the time. There's an option for downloading all of your inbox as a text file to your desktop so that you can have them saved and clear your inbox
How I measure my pullup strength is by my bodyweight.
When I was 175lbs, I could do about 8 pullups. When I reached 205lbs, I could still do 8 pullups.
This tells me that my lats/back got stronger...