No. I dont think so. Recall the distinction between principalled security and the lay persons perception. Our principalled security will be at least as good with higher market share. The amount of attacks directed at Opera only might increase, but it is important to remember that almost all attacks are tried out on all the main browsers. Thus the net result of even more attacks will most likely not be significant. What *will* be significant, however, is that the overall security level of end users browsing will be better if Opera gets a larger market share - due to the facts discussed above.
What's your take on the full disclosure of vulnerabilities?
We prefer that reporters contact vendors prior to disclosing a vulnerability in order to ensure that the impact on innocent bystanders (i.e. end users) is as minimal as possible. When there is a patch available from a vendor, we understand and respect that some reporters want to disclose their findings to the community.