A colleague. A confidant. A contact. Possibly a friend. I'd certainly feel gratitude and deep appreciation for the help someone offered, and I'd hope to return the favor. There are many labels and maybe it's all just words that ultimately mean the same thing. Maybe the argument is semantics and the meaning we each attach to particular titles.
Again, I agree with TR. It's not really about avoiding disappointment. For me it's about sustainability, longevity, depth, history, compatibility, and more than can be gleaned on a message board. This does not diminish my appreciation for those on cyberspace. From what I know, I do like many folks here. Couldn't pick them out of a police lineup!