Multiple signs being posted to buy houses

[Taylor Nunn]

In my area I have seen an obvious increase in signs being posted through out the city saying they will buy houses fast and with cash. 

1) Does this mean that my area is becoming a "hot" market? And should I try to get in asap? (Haven't started investing yet)

2) I've only heard 1 person on the BP podcast that has used signs like that, so I'm curious if any of you have either used signs like those, or ever done business with people who do?

I've heard that they can sometimes be shady, or a good marketing strategy. Let me know what you think!