A few people I know got scammed by cowboys on those sites, but more people have been properly shafted by builders recommended on local forums.
These cowboys infiltrate the local pages on Facebook and other sites by signing up with multiple accounts and recommending themselves.
It's a war out there, so your best bet is to have a look at completed jobs and speak to customers.
Example: if you see a driveway that has been there for a couple of years, so fairly new and hasn't collapsed, knock at the door and ask for the contact.
These cowboys infiltrate the local pages on Facebook and other sites by signing up with multiple accounts and recommending themselves.
It's a war out there, so your best bet is to have a look at completed jobs and speak to customers.
Example: if you see a driveway that has been there for a couple of years, so fairly new and hasn't collapsed, knock at the door and ask for the contact.