@tclfan
The smaller the market share the more secure the browser can be in practice.
Again, obscurity isn't security. Such statements also ignore the fact that there are myriad shared code/projects between browsers. Read, for example, the "Third Parties" section in the Opera "about" page. Nearly every browser uses either OpenSSL or TLS, zlib, libpng, etc. Depending on operating system, they also may share common graphic toolkits (such as GTK) and other code. Then there are the guts that render web pages, some of which are shared between projects. A vuln in one affects more than one, including some of the more "obscure" browsers. So we're right back where we started with security through obscurity, adding that the more shared code there is between projects the more risks there are no matter how obscure one or another project is in terms of market share. A vuln affecting a piece -- like OpenSSL -- shared by various browsers affects the security of all of them.
And that's only a tipping point. You're no safer with one browser over another if the point of entry to your system is something like Flash or some other unrelated piece of software common on enough systems.
"In practice" is the operative part of all of this. User practices count here. I don't click on every link sent to me. I know people who can't resist clicking on links. Am I more at risk with a more popular (and by your reasoning, riskier) browser with my very careful habits than someone else would be with a more marginally-popular browser and more risky habits? Bad habits get more people into trouble than "bad" browsers. And even good habits aren't without risks from things like cross-site scripting.
http://en.wikipedia.org/wiki/Cross-site_scripting@jp
The safest browser is the one with the least functionality.
Correct. The more complex anything is, the more room for error. The safest browser is one lacking java, javascript, plugins like Flash, animated gif support, compression, etc. How boring.
Perhaps a safer alternative is the paranoid system used by RMS, who says he uses wget to fetch everything he browses.
http://lwn.net/Articles/262570/Oops:
http://secunia.com/advisories/product/3416/?task=statistics