Dropquest Guide Step 29 – The Final Step
The answer to step 29: "Dr0pbox heaRts U", which is the ending letter from each step's URL! Thanks for reading everyone 
Dropquest Step 29 (Click for bigger image.)
Dropquest All Done! (Click for bigger image.)
Dropquest Guide Step 28
The answer to step 28 is "1133471056". Anyone know the reference?
Update: Thanks you guys! "You print it out, cut it out, and then fold it into a crane. Across the wings of the crane it says “11696 x 96911″. Take the two and multiply them together for 1133471056" http://yfrog.com/h8sd3atj
Dropquest Step 28 (Click for bigger image.)
Dropquest Guide Step 27
The answer to the step 27 link from step 25 is "badcabbage". Anyone know the reference?
Update: Thanks Aaron, "It’s the notes the piano is playing." (From the file you download in step 25.)
Dropquest Step 27 (Click for bigger image.)
Dropquest Guide Step 25
The reference on step 25 is http://dl.dropbox.com/u/211024/rainbowshell.zip. Anyone know how you are supposed to get that reference?
Update: Thanks commenters, "this is a reference to Chrono Trigger".
Inside the zip is a link to step 27!
Dropquest Step 25 landing page (Click for bigger image.)
Dropquest Guide Step 22
The step 22 file you get after completing step 21 is a reference to a votebox for Frozen Yogurt, which says, "The Dropbox Team is anxiously watching your progress! Though, in a quest like this, it can still make sense for the Hunter to become the Hunted."
Dropquest Step 22 Frozen Yogurt (Click for bigger image.)
This is a reference to the "about dropbox" page featuring engineer Rian Hunter. Click on his name to reach step 25! Almost there!
Dropquest Step 22 Rian Hunter (Click for bigger image.)
Dropquest Guide Step 21
So you've downloaded the zip from step 19? Extract it and look inside for a clue. You have a color, and a file asking for help, "To anyone reading this, I'm in need of some help. Meet me some place where we can collaborate and sync up."
The solution is to create a new folder inside your Dropbox and name it anything you like. Some people claim it must be "1F75CC" but a folder called "test" worked for me. Then, right click and share the folder with another dropbox user. Enter "dropquest@dropbox.com" as the user you want to share with, and share it. You'll now have step 22 inside your folder.
Dropquest Step 21 (Click for bigger image.)
Dropquest Guide Step 19
After completing step 18, you have some braille. Some people say it says "Help BJF", and others say it says "Help BJ". Either way, the solution is to go to: https://www.dropbox.com/help/206. But again, I don't know the reason behind this madness. Someone leave a hint?
Update: Thanks to comments in step 18, the braille reads "help 206," hence the link!
Dropquest Step 19 braille.
Dropquest Step 19 (Click for bigger image.)
Dropquest Guide Step 18
Completing step 17 moves you to step 18. The answer is "Drew Houston", the CEO of Dropbox. Thanks to the commenters for the solution, but again I am not sure of how one arrives at that solution. Help?
Update: Thanks to Shawn in the comments, "Unscramble the names, take the first letter from each = drew houston"
Dropquest Step 18 (Click for bigger image.)
Dropquest Guide Step 17
After going to the link from step 16, you have to "Spell your answer." I don't know why, but the answer is "baff1e" (found it on the forums). Can anyone provide the reference? I'd like to include a full guide rather than a cheat sheet.
Update: Ahh, George says on the step 16 comments that "We use hex colour of clue png!!!" Thanks, George!
Dropquest Step 17 (Click for bigger image.)
Dropquest Guide Step 16
After downloading the file from step 13, unzip it for a text file containing the link to step 17 and a clue.
Dropquest Step 16 (Click for bigger image.)
Dropquest Guide Step 13
After completing step 11, you'll come across step 13:
Dropquest Step 13 (Click for bigger image.)
It took me a while, but I finally found this hint on the forum (thanks to some commenters, too!):
Dropquest Step 13 hint 1 (Click for bigger image.)
The blog post specifically mentions a Japanese restaurant and is post 18, from a Thanksgiving blog post. Here is the link. Clicking the name of the restaurant, Katana-ya, downloads step 16 in a zip file.
Dropquest Step 13 solution (Click for bigger image.)