A blogroll is simply list of related blogs that a blogger recommends. Each blog is an RSS (really simple syndication) feed and is typically listed in a sidebar widget, though that’s not a requirement. The key thing to understand about having a blogroll available to visitors is that it essentially places an additional management burden on the blogger whose reputation can be affected both positively and negatively depending on the quality of the blogs listed. The other consideration has to do with search engines that are allowed to follow external links which is generally the default behavior. When a search engine does so, it may result in an incomplete indexing of the blogger’s site and thus reducing its rank.
In my case, I’m still investigating the cost/benefit of including a blogroll though I do plan on at least identifying the key players/experts in each area of interest. The extent to which I actually am comfortable recommending other blogs is yet to be determined. I will likely start with known credible entities, such as government and reputable trade and news feeds.