Each of these things may account for their failure to reply.
Given this, and the normal etiquette of online interaction, if you don’t receive a response to a first message, keep trying with others. I'm bored to death at work so I decided to check out your website on my iphone during lunch break. I stumbledupon it ;) I may come back yet again since i have bookmarked it.
If your joke isn't funny to that person, it's either a) not funny at all, or b) not funny to him/her. In the middle of this city you're walking around in, surrounded by thousands and millions of people walking, you fear you might be the only one who likes walking?
You might as well find out right away if your senses of humor* line up.*Bonus advice: Please don't just write "I have a good sense of humor" and expect everyone to believe you. It's good to express enthusiasm for shared interests, but don't make them up, and don't be weird about it.
In their study, Hitsch, Hortacsu and Ariely (2010) found that: When it comes to responding, Fiore et al (2010) found that males replied to more first-contact messages than females (26 percent compared to 16 percent).