This happens all the time in SL: you're strolling along, and you encounter another avatar. Being the polite person you are, you open your Chat window and type them a "Hello, there."

. . . And the other avatar doesn't reply. He just stands there like a statue. How rude, right?

Well, not exactly. The most important thing to remember in these situations is, never take them personally. As you'll see after you've been in SL for a while, behind every avatar is a real person -- who is usually multitasking.

That avatar that's standing there, seemingly ignoring you? In reality, he's probably doing several of these things at once:

• Instant Messaging with another avatar. (This is not something you'll be able to see in your Chat window, by the way. Also, the 'typing' animation isn't activated when typing in IM, so you won't see that, either.)
• Engaging in an Instant Message discussion with one of the groups he belongs to. (You wouldn't see this in your Chat window, either.)
• Roaming around in Camera mode, leaving his avatar behind.
• Sorting his inventory - which can get out of hand easily - or maybe building, moving or editing an object. (These are also things you might not be able to see on-screen.)
• Reading his notices, notecards, and other pop-ups that seem to layer and build up between logins. Sometimes it takes me 10 minutes just to click through all the notices, events and group announcements when I log in.
• Answering emails, or surfing the web while in SL.
• Yelling at his real-life spouse, children, or dog.
• Running to the kitchen for a snack, coffee, soda, etc.
• Running to the bathroom.
• It's also possible that his client software is locked up, giving him troubles, or maybe his computer is acting up.

. . . So it's not about you. If you try to start a conversation with another avatar, and they don't respond, give them a few seconds, in case they were busy at the moment you said hello.

If they don't respond at all, then type a quick, polite "Bye" in your Chat, and move on.

There are so many fish in the SL sea, you're bound to meet more-talkative avatars in no time at all.

(And incidentally, if you need to run to the kitchen or bathroom, be sure to afk yourself, so other avatars aren't left wondering why you don't respond!)