For a web-developer the BlogHerald points out the obvious: Checking to make sure your blog presents well on a Mac, in addition to other browsers and platforms. As the article mentions, browser compatibility checks are not a standard practice for many bloggers.

For too many bloggers their view of the internet is via a single browser and a single OS. Any credible web developer will always make sure a web page presents the same in a variety or browsers (IE, Mozilla, FireFox, Opera, etc) and a variety of operating systems (WinXP, OS X, Linux, etc.). In today's culture that also includes browsers in devices such as PocketPCs and BlackBerrys.

Luckily for most entry level blog users, services such as Blogger and TypePad have taken care of many of these issues via their templates. When you start to hack your templates or style sheets make sure you know what is compatible with specific web browsers and test your blog design on as many systems and browsers as possible.