Adobe Illustrator CS and CS2 has incorporated a design element from one of Adobe's other products, Adobe InDesign. This new feature is optical kerning. This is different in that it looks at the entire word and all its letters and then uses mathematical calculations to guestimate what is the best standardized, uniform distance between all letter pairs on the word(s). With the traditional auto kerning which was standard in previous versions of Illustrator, the automatic algorithm did not consider the whole road, rather it look at two letter pairs at a time and made separate kerning adjustments for each letter pair rather than looking at the spacing of the entire word.
Look at the first graphic below. Here we have the standard Auto Kerning turned out. Here Illustrator is again looking at the words "text kerning" just two letter pairs at a time. The results are not bad, but the finicky designer would probably find this unacceptable. The letter pair spacing in "text" is fairly tight, and the first part of "kerning" is also fairly tight. Yet, look at the last four letters in this word...the kerning/spacings suddenly becomes wider and to the observant eye the kerning is very different than in the other parts of the text.
Now we have "optical kerning" turned on. This has done a much better job in making a universal, even distribution of spacing between the letter pairs by examining the entire words. The font used here is "Bank Gothic," which has always posed difficult letter spacing issues.
Bottom line: never neglect the importance of how well your text looks in your logo design. Poorly laid-out text can ruin a beautiful logo.