Here are the official rules for getting bumped up a level so you can message:
Get to trust level 1 by…
*** Entering at least 5 topics**
*** Reading at least 30 posts**
*** Spend a total of 10 minutes reading posts**
By reading they just mean slowly scrolling by a post. This is set by the software (not BFD) to keep spammers out. It works pretty well.