This is a question that I often get asked. First, you should be using both a Facebook account and a Blog. But what works best to get more visitors to your website is the real question, and the answer depends on what you are trying to achieve. Facebook is a great tool once you have a following. Hopefully your followers are really potential new customers.
If you are using Facebook for sending out cute little messages and posting pictures of your vacation, it won't do you much good in attracting customers. On the other hand, if you have a Facebook account that is just set up for business, that's a different story.
The message here is to set up a separate Facebook account, just for your business and post your cute stuff to your personal Facebook account.
After you have set up your business Facebook account, do a deep search using the Facebook search bar, and find potential customers to add to your following list. As an example, if you sell cut-glass flower vases, you might want to invite all owners of flower shops to follow you. There are over 2,100 flower shop listings on Facebook that I recently found. It will take some work, but sending out invitations to these and other potential customers is well worth the effort. Just make sure when you do invite them to follow you, you send something that is of interest to them. Remember you are trying to build a relationship, not to try and sell your products with the first contact that you make.
I won't go into what you should send them via your business Facebook page. That's a whole topic unto itself.
Now on to Blogging!
I believe setting up and using a Blog is a lot easier than using Facebook or other social media sites. Blogs were used for short communications the way a Facebook or LinkedIn account is now. A Blog should be used to send out articles, lists of tips, helpful suggestions, and recommendations. However, using it to publish articles is the real key.
Why publish articles? The first thing to understand is that the search engines (especially Google) love content. By content I mean a 300-500-word article written about a subject that relates to your business. You are the expert in your business, so coming up with an article every other month shouldn't be that difficult.
A good article will have a greater chance of being recognized by the search engines. The search engine will index your article and list it in its organic search results. On the other hand, a short little note on your Facebook account is not going to get spidered and indexed by the search engines. Good content on a Blog will almost always get spidered and indexed by Google and other major search engines.
The more listings that you have in the organic search results of the major search engines, the more chances you will have that someone will find you, visit your Blog, and eventually visit your website. That is exactly what you want to happen, and using a Blog is the way to do it.
When you write an article for your Blog, remember that you want to get your article to show up on the search engines. So be very selective in which keyword/phrases you use when writing your article. As an example, if you are writing an article about the variations in quality among various manufactured cut-glass vases, use the keyword/phrase "Quality Cut Glass Vases" several times in your article. Also, use this keyword/phrase in the title of your article, use something like: "Quality Cut-Glass Vases: Price is Not Always the Best Guide".