Facebook is a as good of a source for proving a relationship as other sources! What I myself meant all the way back was that writing that one is married on facebook isn't really a powerful thing
in itself. It's one of many things that she needs to get! You need legal documents and you also need other support evidence proving it's genuine. And yeah, in response to Honeybird: some of my friends do make fake relationships on facebook simply due to an inside joke.
The "mutual friends" part could be a "so what?" thing -- at least to me. I know so many people who have tried to add me as their 'friend' when I didn't know them -- they were friends of my other friends. Though, if you got one of those 'mutual friends' to write a letter, then the 'mutual friend' thing could be validated.
I personally used facebook to message notes to my husband and contact him, but I also used emails and non-digital evidence like receipts and other proofs. Basically, it's probably good to get a variety of proof.
As for smrty: I think the fact that more and more people are beginning to use internet for maintaining their relationships and for everyday communication, it is becoming a legit form of proving relationships are genuine. Sure online relationships could be entirely orchestrated. Like my skype-to-skype calls could just be me calling my husband and letting the time pass without actually chatting with him. Or our emails could be entirely faked and scripted. It would take a lot of effort but it's possible to create a fake relationship with lots of evidence. But, ha! maybe if you really take that much effort, maybe you should be allowed to come to Canada as a PR..
Though, I am not saying that internet relationship are all fake or weaker than other forms nor am I saying that the evidence from internet sources are weak. Either way, it's safer to have more than
one type and source of evidence for the entirety of your relationship to prove it's genuine.. I would think. Internet evidence but also tying it in with non-digital physical evidence is best thing to do, no? Though a solely internet-based relationship with tons and a variety of proof that have genuine and real conversations is excellent as well.