I wouldn't say it's changed the way I use forums at all, but it certainly has relegated them to a lesser place of importance for me. Having said that I am not exactly a big forum user anyway.
Forums are great for sharing your work with like minded modelers, in appropriate areas of focused topics of interest with smaller groups of people. You can start a thread focusing on your model and the entire thread can basically talk about your model. You can then look around the specific area of interest that you have and comment and converse on similar models with a small group of people.
Facebook has opened the door so much wider as far as audience is concerned, you probably wont find a non English speaker coming in here and commenting on my build, but that same person may be very inclined to simply 'like' your post letting you know that he/she 'digs' it, or they may even write a one word comment in their native tongue like "magnifico!" and if it is a word you don't understand, there is usually a 'translate' option directly below it. You can post a photo and someone sitting in the dentist waiting room scrolling through on their phone can simply click 'like' and give you a sort of silent boost of support and encouragement without having to log in, post a bunch of text and hit submit.
I think the use of the term 'friends' conjures up the wrong idea to many people, as like has been mentioned, most of these people may not even be real friends. In simple truth, it is merely a label and facebook offers many other labels and groups as well as the ability to create custom groups in which people can be assigned. You can have many different groupings of people from closest family to most distant frienemy and each group is only allowed access to what you have allowed them access to, it's only a free for all if you allow it to be.
While they are definitely a bit convoluted and take some figuring out, facebook's built in options allow you complete control over who sees what, and who can't see what, so that fellow modeler who sent you a friend request because he read your article in a magazine half way around the globe can be assigned to the 'acquaintance' group, thus keeping him from seeing pictures of your kids at the family cookout, or your hot wife/gf in a bikini on the beach, leaving those photos and posts for the eyes of the people you've allowed only.
I have tons of modelers who I have allowed on my facebook, but they can only see my modeling posts. Others whom I've met and/or hung out with and/or have known and talked to for years can see a little more of my personal life. Local friends and family are allowed an even bigger window in my life since their kids may be in those same photos etc. I can set up an album and place photos in it and only allow one specific person access, I can make things public, private, friends only, friends of friends and the list goes on. I can completely customize it if I want to put in the time.
I often read/hear people saying that there is no privacy but the truth is, it's actually the opposite. There are many options and abilities to actually have more privacy. If there is a person who causes trouble, or posts nasty stuff, only goes on political rants, you can 'unfollow' them removing their posts from your 'news feed'. If you still see them posting crap on friends facebook pages and it turns you off you can simply block them and you'll never see their posts and they will never see yours. Ever. It's that simple really and it's not quite as cut and dry on forums.
I know one older gentleman whom I used to consider a good friend who has since stopped posting here because of the facebook feed on the right of the homepage. I went out of my way on several occasions to help him with things, made him custom videos that only he got to see to explain his questions and supported him in everything he did, heck we often spoke privately and even on the phone a few times. His attitude was that all of the views on his threads were now from facebook people who didn't do anything to support him, which is just not true. That's not how the facebook feed works, no one is on facebook looking at his stuff through the feed and not contributing. View counts vs replies have always been hugely uneven on forums and he never made much of a stink on other forums when he had 350 views and 10 comments but whatever, how do you even go about explaining something like that to an older man whose made his mind up even if it's down right silly. Often times in life, the biggest misunderstandings are based on a lack of facts and an extra helping of emotions used to make decisions.
So while it's clear that facebook is not for everyone and does have it's issues, I think if more people took the time to get well informed and perhaps even shown how to use their settings, most people would find that they are in far better control over who sees what and who they share their stuff with on facebook, than they are on your average forum.
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In case that was all tl;dr than short answer, No. It doesn't change the way I use forums, but it does change the way I reach my audience.
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