What does “effective” mean to you?
Understanding what you mean by effective is the only way to quantify if the Facebook ads are working.
Generally though, Facebook ads are a great way to drive traffic to a blog, gain followers and build and email list to promote too.
Building an audience to advertise to with Facebook Ads.
More recent additions to custom audience options gives you more audiences to advertise to. You can also install the Facebook pixel on your blog and create an audience of people who read it.
Next you can build a “lookalike” audience in the Facebook Ad manager. This is a group of people who Facebook “thinks” will like yoru content. People similar to the one who are already visiting.
Building an email list to continue to deliver content outside of Facebook.
As soon as you start running ads you should also be making an effort to build an email list of people who are interested in your content. With an email list, minus a few ongoing costs, reaching your list is free. So once you have someone on your email list you can continue to email them many times. Growing yoru email list will magnify the work you do with paid Facebook traffic.
This can be as simple as sending out a notice that new content is posted or adding additional value for people who get your email. A lot of people offer some kind of problem solving “bribe” to get people to join the email list. It’s a matter of testing.
You can also reverse the traffic flow and use Facebook ads to get people onto an email list first and then promote your content.
I’ve seen clicks for blog content range from .0002 cent a click to over $1 per click (visitor). It depends on how well you build your ads and target people.
It can also take time and a lot of experimenting to really find out what works for your audience. I warn people to think longer term when diving into paid ads. They have to learn the interface and how to run ads, as well as what their audience really likes.
A quick thing to look at is if you post organically and have one or two posts that have done well organically, you can promote those posts as ads. Usually a post that does well organically will do ok with paid traffic. Not always, but it’s an indicator.
Amplify organic traffic:
If you already have organic traffic to your blog then you can easily build an audience around current visitors or even people who visit multiple times recently.
Paid Facebook traffic is really useful for building your blog as long as you have a plan and a way to monetize the traffic or simply have a budget to grow your following.