Why is exploration sale called exploration?

Most of outpost are in sets or want offers, so not many links here

Seller below 1.2 keys:

http://www.tf2outpost.com/trade/23657774 2 weeks, has lowered his/her price

Sellers for 1.2 keys:

http://www.tf2outpost.com/trade/23850101 19 hours

Sellers for 1.3 keys:

http://www.tf2outpost.com/trade/23857054 1 day

http://www.tf2outpost.com/trade/23848250 2 days

http://www.tf2outpost.com/trade/23821144 4 days

Unsold at 1.5 keys:

http://www.tf2outpost.com/trade/23843030 2 days

http://www.tf2outpost.com/trade/23833651 3 days

So, 1.5 keys doesn't seem to sell anymore and 1.3 keys is the most common trading point, so a price of 1.2-1.3 keys

All counter/supportive proof is welcomed