Great advice.....especially if you type and think at the same time - vs. thinking then typing then thinking again. All good tips but IMO the most significant is not being reactive....where you could hurt yourself the most.

http://blog.brand-yourself.com/2008/how-to-leave-effective-blog-comments/

How to Leave Effective Blog Comments
November 24th, 2008 by Pete Kistler

Commenting on other people’s blogs demonstrates your ability to produce insightful reactions to other people’s ideas. Employers will search for your name in Google, and they will find the blog comments you’ve left - which is a good thing. Blog comments give you a way to stand out from your peers in a super-competitive market.

Employers want to see you commenting on blogs because it demonstrates to them that you’re an active member of your niche, you’re passionate enough to participate in conversations related to your area of expertise, and you’re intelligent enough to add value to conversations online that relate to your career goals.

When commenting on blogs, here’s a checklist that will ensure you’re leaving as strong an impression as possible.

Blog comment checklist:

Your blog comment…

Adds value or new ideas to the original blog post
Accurately and concisely answers someone else’s question
Has no spelling or grammar mistakes (it can’t be edited later)
Relates to your area of expertise
Is not hyper-reactive (doesn’t make you seem emotionally unstable)
Does not put anyone down (if arguing, provide counterpoints but don’t attack individuals)
Includes facts and links that back up every claim you make
Includes your name (the one you want people to find you with when they search for you in Google)
Includes a link to your website (boosting the Google rank of your site and leads more people there)
Includes your tagline (a short phrase that describes to strangers what you do)
Commenting on blogs leaves a trail of “digital breadcrumbs” that people (employers, co-workers, bosses, etc.) will find when they type your name into Google. Always keep this checklist in mind.

Blog comments, forums comments, book reviews and contributing to wiki articles are just a few ways to leave a trail of breadcrumbs online that builds a web presence worthy of remark, differentiating you from other job applicants who haven’t spent time to establish a strong presence online.