<p>Reputation and badges are not simply rewards (and indeed, as rewards they're  fairly flimsy when one can earn very real rewards putting the same effort into other activities).</p>

<p>Instead, reputation and badges also (and perhaps more usefully) serve as signals to others, but they signal different things.</p>

<p>At the present time I have a similar reputation to whuber (and I hope he will excuse me mentioning him in my answer), but he has a substantially higher number of "Good Answer" badges than I do (about 5 for every 3 I have, even though I have answered more questions). Good Answer badges are quite rare, so someone holding a lot of them tells you something important about the standard of their answers.</p>

<p>More of the story comes when you look at the tag badges, for example, whuber has a <code>spatial</code> tag badge, spatial statistics being a topic on which he has vastly more knowledge than me. Knowing that he has that tag badge and I don't might help to indicate his relative expertise on the topic.</p>

<p>There are some users on site that have a large amount of reputation that has been mainly gained from asking good questions. That certainly indicates important contributions to the site, but might give you a different view of their answer to some question when compared to a user of similar reputation which has been almost entirely earned on good answers.</p>

<p>Reputation tells our readers only part of the story. Badges tell another part. Both can be useful in giving users a picture of the likely value of what is being said (if it's not otherwise clear). It's no guarantee of course -- anybody might have an off day and give an answer below their usual standard, for example, and ultimately an answer must stand on its own merits -- but such indications can sometimes be useful.</p>
