Techies is "mine stacking": placing mines directly one on top of the other so that the enemy can't tell how many mines there are at a location even if they have True Sight. In wc3 DotA this wasn't difficult to accomplish because you could portrait cast. This doesn't work in DotA 2, making life significantly more difficult. However, I did figure out a way around that:
Techies players mine the rune, the river, and stack 
Remote Mines at T1, they don't know what to do anymore except to keep stacking Remote Mines. Of course Remote Mines are great anti-push, but if the enemy team doesn't push, you become completely useless as a hero.
Techies can be one of the
most effective 5-position supports in the game. The key is to focus on vision and ridiculous area denial:
Techies to the roster saying about how he's actually a useless hero, countered by a 250g item, countered by 
Gem of True Sight, no one serious will ever use him, the usual (further fueled by the recent showing in the Allstar game that played him extremely weirdly) - so I decided to actually write up an inside look at the competitive history of Techies and his effect on the game and how we might see him used in the future.
