Lawyers should know that if the blog contains information regarding the lawyer's services, the blog should conform to the lawyer's state rules on advertising, particularly those addressing false and misleading advertisements. Some additional risks are:
Ex Parte Contacts - Lawyers should avoid interacting with a represented party and not contact a party already represented by counsel via the represented party's blog.
Duty of Confidentiality - When discussing any representation, past or present, lawyers should remember that all information obtained in the course of the representation is CONFIDENTIAL (see the COMMENT to Rule 1.6). This includes information obtained from public sources and information generally known. So use only the most general of generalizations, no client names or identifying information, occupations, etc.
Is the Blog an advertisement? - Is the interactive portion of the website for discussion only or is there a link to contact the firm? Link = advertisement.
Firm Policies - Employers should have blogging guidelines to avoid law firm exposure and blogs should have disclaimers that it is not legal advice and cannot be relied on for such.
Copyright Issues - Who owns the blog and its contents? Copyright is automatic and posting online is not a waiver of copyright.