Your Online Activities--You Are What You Do
In addition to the information you publish, with the expectation it will be read by others to form a perception of you, the online actions you take at a wide array of sites are visible to others, and contribute to (or detract from) the parts of your persona that have been crafter with greater care.
Also, the Internet is a network of strangers, and most users take what they see online with a grain of salt: they don't really know who can be trusted, and have varying degrees of antipathy toward unknown sources, but most will be skeptical of an unknown source until they've had additional exposure to it and have developed trust.
Understanding Reputation Management Engines
An earlier chapter discussed Google's use as a reputation system. A short recap: a Google search pulls up information from a wide range of resources, and people form an impression just by reading those search results. So not only what you publish, but what others write about you, will be visible to anyone searching for information about you.
An example given discusses online product reviews at eBay: the reputation of sellers and buyers are openly discussed by those who have done business with them, and this is often very influential in determining their future business. A seller with a bad rating will get fewer and lower bids than one with a good rating.
Especially when a purchase is high-dollar and a vendor is unknown, people go the extra mile to find ratings and reviews, so it's especially important for a vendor not only to treat its customers well, but also to ask them to rate their buying experience.
The same is true of manufacturers: people rate products at sites such as amazon.com, and products with poor ratings have poor sales than products of similar "quality" that have higher ratings. It's the rating, moreso than your product description, that "sells" your item over a competing one.
There are also third-party review sites, where customers share opinions on a wide range of products, services, companies, employers, etc. Not to mention the various "slam" and "sucks" sites where disgruntled customers gather to commiserate and vent their collective spleens.
There are even ratings of raters: on sites where customers rate products, other customers are encouraged to rate the rating (was the recommendation useful to you), largely as a defense against sellers who attempt to stuff the ballot box with fake reviews.
Quick Clicks That Can Harm Your Reputation
The author skims over what is already common knowledge: your employer keeps track of your internet usage and e-mail, and you can be fired for surfing inappropriate sites or sending inappropriate messages.
Another word of caution is about forwarding e-mails. There have been a number of incidents where a message sent to someone in-house was forwarded, unedited, to a customer, which caused an uproar. You have to be careful about what you write - to anyone.
Becoming Well Respected in Virtual Worlds
Virtual worlds are becoming more popular, whether they are the environment in a computer game or virtual chat environments (second life). The author chats a while about these, but my sense is that this arena is too new for there to be much reliable knowledge or proven techniques, and I still see them as faddish.
In general, an online game or virtual world is a fantasy space, and understood to be so by all involved. Reality is an intrusion. For that reason, it may not be wise to use your real-word information as part of your online persona.
In some spaces (second life), it may e of value to participate as "yourself" or represent your brand. In those instances, remember your purpose in being there: you may have to opt out of some of the "fun" for the sake of keeping your reputation clean.