Hi! Welcome to the forum! :waving
Good question to jump in with as well...we've been having a number of discussions lately about the Body of Christ, assembling together, etc...
There is no doubt that CF.net is indeed a Christian community. For some, it can even be their "church", the place where they fellowship with others.
And, there are definite similarities with a local church body here...we certainly love each other, today many of us are rejoicing with two of our members (married couple) who just had a baby, grieving over the death of another member last month, uplifting our sister living through the devastation and chaos in Japan, praying for others for various needs. I know when I have a need that I want the brethren to pray for, I ask here just as I as at my church.
We certainly challenge, discuss, exhort, and encourage one another towards a deeper understand of God's word and how to live out our faith in the world.
We laugh together, get angry with each other, cry with each other...all just like we do in a local church body.
I have some friends here that I feel much closer to than most of the people that I know in "real" life.
But, there are differences and I believe those differences are very important...We cannot commune with each other...and I believe communion is very important...we cannot lift our voices in song with each other, we cannot corporately worship the Lord together...we cannot join together with each other to baptize one another, another vital function of the church...although we can certainly exhort each other to remember their baptisms.
Myself, I find that the differences do not make up for the similarities...for a number of years, I did not have a local church body, and while that was why I wound up seeking fellowship on-line, and still cherish this on-line fellowship...I find my walk much more fulfilled, challenged and mission minded by being a part of a local church fellowship.
But that's me...one thing you are going to find out fast is that there is a wide variety of opinions here at CF.net! ;)