KenB - 12:32 pm on Aug 23, 2006 (gmt 0)
Probably a good time to mention that Opera spoofs user agent very easily (and natively, out of self defense for bad code). Not all log anaysis packages pull out true numbers for Opera.
Properly detecting Opera when processing server logs is a trivial matter as it ALWAYS includes the word Opera in the UA string unless explicitly set not to for a specific site in one of Opera's config files. The highest market share I ever noted for Opera on my sites was 0.57%