I've made a simple pool for my blog readers. I ask them why don't they use Opera as their main browser, and here came across some answers:

• At first time they used Opera, they found that Opera's cache is too strong. And it's a problem for a web developer because they can't see the change right away. Well, if they know about Shift+F5, it's not a problem at all.
• They wonder if they can found something like Firefox's plugins. They don't want to switch to Opera because they afraid of loosing the plugin's benefit.
• Some people using glubble to protect their kids from unwanted page, and Opera doesn't have this such thing.
• Because Opera is not open source. Well, they don't really need the source code but they afraid if someday Opera company will be closed. Thus, Opera users will be dumped away. But if Opera were open source, there will be another group who would give Opera a re-birth.
• A friend was afraid of intergalactic law violation when using a little trick to open Google Docs :doh:

Last but not least, this little sweet girl was saying that this question is the same as "Why Mac users aren't as many as Windows users".

From this pool, now I have idea why don't they use Opera: because they don't know much about Opera. Then it's a task for Opera company to spread more information about Opera and its benefits. :cheers: