What connects?

This list is by no means exhaustive, although it is in chronological order :)

EDIT: Added one more, on public demand:

Cracked by: Raghuvansh, Urthstripe, Manish Achuth, Ananth, Shwetha Maiya, Dibyo, Anonymous, jowens, Sumanth Patlolla, raklodramA, Bipin Banavalikar, shrik, Thejas V R, amarendra, rickde, username, Rogi, Bharath, Rahul Rajeev, mankuTimma, Swarun, Logik, anurag, badideabear and Manoj Venkat