I stand corrected: it's a 5Gb bonus all up. Seems 500Mb is a seperate bonus for using the beta, and 4.5Gb is especially for this offer. Upload that little bit more if you haven't already :)
Probably should have added this earlier haha, but if you felt like being nice and hadn't already signed up - please use my refferal link :) http://db.tt/IKR2BhS0
Thought I'd stick this up given no one had yet and Dropbox posts generally go down well.
The way it works: first you install the new beta client of Dropbox which has automated photo and video uploading. You get a bonus 500MB as soon as you start using this feature, and an extra 500MB for each successive 500MB you upload, to a maximum of 4.5GB bonus data on your account. Better get uploadin'!
As Gizmodo advises:
Of course, as with any test software, you should be careful with backing up your backups before you dive right in…
Which is probably a very good idea.
ciab (comment below) has a possible method for getting the bonus data without uploading 4 gig. I would suggest if you do this at least have a good play around with how the new feature works - they're doing this as an incentive for you to test it so it could be nice to help them out a bit :)
via Ghacks via Slickdeals via Gizmodo. Referencing YEAH!
This worked for me too, Windows 7 64-bit, no dramas at all.