Wikipedia, of course, is a great public domain resource where you can 'lift' content without worrying about paying for rights (though it is of course right to attribute your materials to your source.) Here is the online encyclopedia's article about Copyright.
I will almost always communicate with you if I use your name or quote from your materials externally in this blog. Comments on closed list serves may not be public, or quotes from your own website (or more significantly) your graphics may not be in the public domain and subject to copyright. Since I make it my practice to only attribute comments and materials about individuals in a positive context, you will likely have little reason to complain (especially since this site now has high search engine rankings, and the link-back to your site if used will probably help your own search engine rankings).
One great advantage of blogging is that you can quickly catch and edit your comments and postings -- so if I inadvertently slip up and write something that is wrong, misleading, or offensive, I can hit 'delete' and the post is gone. (If I wait too long, alas, Google may archive the offensive posting, but that is one reason I let people know about the postings -- so that we can resolve issues right away.)
Nevertheless, when you are copying stuff you should be aware of copyright, especially if you are lifting materials for your own marketing interests. This is the case if you are using the printed media, and it especially applies to photocopying stuff. Say, someone writes a great article you would like to include in your marketing materials. You certainly cannot just run off the copies and distribute them! You should also be careful with music -- be sure that the music you are using on your website is either public domain or you receive direct permission to use these resources.
Fortunately, you can avoid many problems by using rights and permission services, or stock photo/music services. Especially if you wish to photocopy materials, use the Copyright Clearance Center in the U.S. and, in Canada, Access Copyright. Once you set up an account, you will only need to pay a modest fee for copies, and your activities will be totally legal. The copyright agencies have international agreements with their counterparts; allowing you safely to "lift" materials from virtually anywhere in the world without fear of copyright violation.
Digital copyright issues are more complex because common practice these days is to violate copyright in many situations, and even the copyright owners have mixed feelings about the practice. Is a cross-link from one website to another, or the lifting of some materials with a link a copyright violation? The cross-link is probably okay, but the lifting may be a technical violation if it goes beyond modest fair comment levels. Ditto for images. But most publishers are tolerant, especially since link-backs help to increase the search engine rankings of the source -- thus improving its effectiveness and value. In our website rebuild -- where this blog will have a prominent place -- we are arranging with Access Copyright to set up a digital rights management system that will allow you to forward copies of the site content to friends and give you resources should you wish to republish the content for commercial use.
Many people believe that existing copyright rules are outdated, and conventional publishers -- especially in the music industry -- are struggling with what they perceive to be blatant piracy on the web. They have a point in that intellectual property and artistic works at least in theory should have some level of protection. However, many musicians, creators, and bloggers are finding freedom to express themselves and find the free distribution of their work across the web invites direct orders and business.
I only had to enforce copyright once from a website, when I saw someone overtly lift an article from one of our printed publications and use it without any permission. I probably wouldn't have been offended, but the site owner put very direct and 'loud' notices on his site that all rights are reserved, and that if anyone wishes to use material from the site they must obtain permission first. The site owner sent me a couple hundred dollars to pay for the rights, once I complained.
Nevertheless, in your marketing resources, if you are using other people's material -- whether it be words, music, graphic design, or photos -- check to see that the material is in the public domain, or that you have their permission first. You most likely won't be jailed and will find that if you need to settle for copyright violation, your financial penalty won't put you into bankruptcy. But I would hate to throw away thousands of dollars of printed material because of a simple copyright violation.