As an introvert, I "feel" loneliness much less often, and possibly less acutely, than many extroverts. I'm usually content in my own company, and have many interests that are "sole" activities such as building models and reading. That said, there are times when I look for connection with people. I can identify such times, because that's when my usual interests don't interest me.
Sometimes the CC chat rooms satisfy the desire, though I find that some individuals monopolize the mic with either loud aggressive opinions on everything or with silliness that simply irritates me. Sometimes though, I find sincere and reasonable people there who are able to engage in light, relaxed conversation.
On the rare occasions that I do feel genuinely lonely for human companionship, I lament my introversion and isolation, as that is when my list of friends seems very small.