I'm not saying this is true for all relationships. I think that these methods of communication can enhance an already established relationship, or start a new one. But for a relationship to last on those alone is tough.
Many of us spend a lot of time online (I'm guilty as charged), and we "live" in a virtual world. I think that the adversary can use this against us to minimize the need for actual person to person contact. He minimizes the need for a body by getting us to believe that living virtually is enough. It is not.
Living virtually leaves your soul hungry. It might give you little fixes (aka adult conversations) but they always leave you wanting, needing more. And if we keep turning to virtual sources for nourishment for our soul, it will never be satisfied.
Now, these are extremes of course. This is a big reason I got myself off Facebook. I was starving so to speak. There was life all around me, but I was wrapped up in the virtual world. Most people can self-moderate. I missed that lesson somewhere along the way and lack that skill.
So what does this have to do with friendships of convenience? Well, I will tell you. ;)
In the past, you were friends with your neighbors because they were close and convenient. In today's world, not many of us even know our neighbors. We meet people at work, at school, online, etc. Then we "Facebook" them or get their number and text them. They could live next door or on the other side of the world. It doesn't matter anymore if they are physically close to you anymore or not. It doesn't matter if you run in the same circles or not, you can create a new one.
For me, I tend to nourish the relationships in which we have a common form of preferred communication. It's convenient for me, it's easy. I don't have to get out of my comfort zone. So if you are a fan of indirect communication (texting, email, etc), I'm your gal.
This also makes it easier to leave "friends" by the way side. When I left Facebook, I knew that many of my "friends" would be heard of no more. That was okay with me. Not that I didn't care for those friends....I am a friend hoarder afterall. It was more that I needed to see who wanted and was willing to invest in me with time and effort and vice versa. It's been interesting to see how the chips have fallen. Ones that I was worried about losing, I haven't. Some whom I didn't think would stick around have. And some that I'm sure would be there have faded into the distance. I don't think more or less of people either way. I just find it interesting. ;)
There are certain people and relationships that I miss. But what amazes me is how many people say that they miss me being on Facebook. I think it's my fabulous humor and whit that they miss the most. ;)