what are these or gates for?
Boy that's a nasty comment discussion happening, sadly you can't thumb down comments that are incorrect (such as Don Joe's). 

Onwards to the question at hand, tying outputs together. In the comment section you guys seem to love setting outputs to the same logical value, that's all fine and dandy. But so far none of you have tripped over the major problem. 

What happens when one gate is outputting a logical zero and another gate is outputting a logical one? You'll get two transistors burning, one transistor that is trying to make the output high and another transistor trying to make the output low. If the transistors have equal \$R_{d_{on}}\$, also known as the resistance of the transistor while it is conducting, then the output will be inbetween of high and low. 

So if a logic high is 5 V and a logic zero is 0 V, then the output will be 2.5 V. The resistances of the transistors will most likely be in a couple of ohm's range, if they are like in the 74ls series. Let's assume both transistors have an \$R_{d_{on}}\$ of 5 Ω. The power lost in the form of heat in one of the transistors will be \$P=\frac{V^2}{R} = \frac{5^2V}{5 Ω} = 5W\$. One, if not both of the transistors will let out a magic smoke. 

TLDR; Transistors will burn up.