There is a good deal of anecdotal evidence that shows a cyclic behavior within highly functioning technical communities.  Beginners enter the community through reading and responding to blogs, asking questions in technical forums, or perhaps by attending user group meetings, with the intent of seeking general guidance or to ask for help with a specific problem or scenario.  Seasoned professionals within the community step up to offer assistance to these seekers, sharing their own experiences and best practices along the way.  As the beginner spends more and more time asking questions of the community, he/she collects a significant amount of knowledge and experience, eventually reaching the point where the student becomes the teacher, and goes on to share his/her knowledge with the next group of beginners through blogging, forum participation, and even delivering technical presentations.  As such, the cycle of knowledge transfer goes on and on.

Many professionals, myself included, who have been through this cycle enjoy sharing with others what we've learned because we have experienced firsthand the impact of having expert guidance in the early days of a technical career.  By altruistically volunteering their time and expertise, experts help each new "class" of beginners to start off stronger, and the community as a whole is made better.

But there is another, often unplanned, effect: when you spend time helping others, you also improve your own skills.

It's not difficult to reconcile how this happens.  Most of these experienced contributors have a sincere desire to help others, and as such they work to give the best advice possible.  As a result, they often spend extra time reviewing the solutions or methodologies to ensure their accuracy and relevance.  In addition, lending one's expertise to others often leads down paths not taken before, which helps to expose new areas of technology and broadening the skillset of the expert. 

Add to that the fact that these seasoned professionals will often cross-pollinate with other mentors and learn some alternative approaches to problems, further broadening their expertise.  Further, these mentors have a certain stature within the community, and they don't want to give flawed advice - particularly in a public forum - so they often work a little bit harder to verify the information they share. 

So, spend some time helping out a less experienced colleague.  You'll better the community, and could improve your own skills in the process.