How far can I run a RG-6 cable for networking

[Apple Electric]

I am trying to use the existing rg-6 in a building for internet but am not sure how far a coax can go and still get a good signal strength

 

[Pyroflea]

It tends to vary depending on the source, and obviously cable quality will be a determining factor as well. The general consensus seems to be ~150', but reports of more than double that length working flawlessly are not uncommon. How large of a run are you planning on doing?