It has long been news that HTC has agreed with Dropbox to give its users an additional free space. Truth sounded numbers from 3 to 5 free gigabytes for the user. In fact, everything is a bit wrong.
According to the conditions , the first user registered on Dropbox with an application installed on a phone with Sense 3.5-3.6 and viewed Get Started will receive 3 gig for 1 year. Users of phones with Sense 4.0 will receive 23 gig for 2 years.
Judging by the wording in the conditions, it is worth waiting for your phone to receive Sense 4.0 (if this happens in the near future). It is then more profitable to go through Get Started to get more space. The promotion runs until December 31, 2012.
With my HTC Desire HD, I now only got 3 gigabytes.